(CNN) -- The world is waiting to see whether the United States will strike against the Syrian regime -- and whether anyone will join in.
U.S. President Barack Obama said there's no doubt Syria used chemical weapons on its own civilians on August 21, and he wants to launch attacks, but he first wants to get Congress' approval after lawmakers come back from recess next week.
Here are the latest developments:
-- The Senate Foreign Relations Committee will take up a revised authorization bill Wednesday for the use of force in Syria, Democratic sources told CNN. The bill limits the authorization to 60 days, with an option for an additional 30-day deadline, and makes clear there would be no U.S. boots on the ground, according to a copy of the text provided by a legislative source.
-- The Obama administration is "not contemplating" what it would do if Congress votes against authorizing U.S. military strikes against Syria, "because it's too dire," Secretary of State John Kerry told a Senate committee Tuesday.
-- Kerry defended the administration's decision to delay strikes against Syria to seek the approval of Congress, telling a Senate committee in a reference to Syrian President Bashar al-Assad, "I would far rather be playing our hand than his at this point in time."
-- Kerry said Tuesday that the authorization from Congress being sought by President Obama to strike Syria "is a limited, targeted effort to focus on deterring and degrading the chemical weapons capacities of (al-Assad's) regime."
-- After being pressed on previous comments that appeared to open the door to potentially having U.S. troops in Syria, Kerry said firmly on Tuesday, "There will not be American boots on the ground with respect to the civil war." Kerry spoke as Congress is mulling whether to authorize military action in Syria.
-- The Syrian regime's reported use of chemical weapons is a threat to U.S. security interests in part because it would embolden other regimes, like North Korea, to use their stockpiles, and encourage other governments to acquire them, U.S. Defense Secretary Chuck Hagel told the Senate Foreign Relations Committee on Tuesday afternoon. The risk of chemical weapons proliferation in the Middle East specifically "poses a direct threat to our friends and partners, and to U.S. personnel in the region," he said.
-- The U.S. Defense Department's plans for military strikes against the Syrian regime is tailored to degrade Syria's ability to carry out chemical weapons attacks, and deter it from further chemical weapons use -- not to resolve the Syrian civil war, Hagel said.
-- Secretary Kerry said Tuesday that if Obama orders a military strike on Syria, such an action "will make us more secure," including by making it difficult for Syria's leadership to use chemical weapons. "The absence of taking the actions will, in fact, be far more threatening and dangerous and ... ultimately cost lives," he said on Capitol Hill.
-- Joint Chiefs Chairman Gen. Martin Dempsey said Tuesday that he's been charged with giving Obama military options "to deter" Syria's government from using chemical weapons -- or, in his words, to "change the regime's calculations."
-- Kerry said Tuesday that not striking Syria could, in the long run, cost the United States allies and make things more challenging as it deals with crises worldwide. "It would make our life very, very difficult with respect to North Korea and Iran," he said, singling out two of Washington's adversaries.
-- Opening a hearing on Obama's call for military strikes against the Syrian regime, the chairman of the Senate Foreign Relations Committee said Tuesday that he supports the president's decision. "Yes, there are risks to action, but the consequences of inaction are greater and graver still: further humanitarian disaster in Syria; regional instability; the loss of American credibility around the world; an emboldened Iran and North Korea; and the disintegration of international law," U.S. Sen. Robert Menendez, D-New Jersey, said.
-- Menendez cautioned against inaction in the face of a possible U.N. Security Council veto, in an apparent reference to Russia and China. "Are we willing to watch a slaughter just because the patrons of that slaughter are willing to use their veto at the United Nations to allow it to happen so their beneficiary can stay in power?" he asked.
-- Evidence of a chemical weapons attack in Syria proves "beyond any reasonable doubt" that President al-Assad's government was behind it, Secretary Kerry told the Senate Foreign Relations Committee. He acknowledged concerns over faulty intelligence on weapons of mass destruction out of Iraq ahead of the U.S. invasion in 2003, but reassured committee members that the U.S. "intelligence community has scrubbed and re-scrubbed the evidence" out of Syria. "We have physical evidence of where the rockets came from and when. Not one rocket landed in regime-controlled territory. Not one. All of them landed in opposition-controlled or contested territory. We have a map -- physical evidence -- showing every geographical point of impact, and that is concrete," he said.
-- Kerry said that the use of chemical weapons in Syria is not about crossing Obama's so-called red line, but that "this debate is about the world's red line -- it's about humanity's red line -- and it's a line that anyone with a conscience should draw."
-- House Speaker John Boehner said he supports President Obama's call for military action in Syria. "Only the United States has the capability and the capacity to stop Assad and warn others around the world that this type of behavior is not going to be tolerated," he told reporters Tuesday.
-- Boehner says it's now "the president's responsibility to make his case to the American people and their elected representatives," his spokesman said.
-- Senate Majority Leader Harry Reid is confident that senators will authorize military strikes in Syria, a Democratic source familiar with Reid's thinking told CNN. The source says authorization is likely to need 60 votes to overcome a filibuster and Reid thinks the votes are there.
-- U.S. Rep. Alan Grayson, a Florida Democrat, deplored the idea of military action and said "we are not the world's policemen." "A strike is not going to accomplish anything useful," he told CNN on Tuesday. "It is not our problem. It is very expensive and it's dangerous."
-- House Majority Leader Eric Cantor says he'll vote to provide Obama "the option to use military force in Syria." "America has a compelling national security interest to prevent and respond to the use of weapons of mass destruction," the Virginia Republican said in a statement.
-- Obama, before meeting Tuesday morning with members of Congress about possible military intervention in Syria, said he believes the U.S. military plan is appropriate, proportional, limited, and "does not involve boots on the ground." "This is not Iraq, and this is not Afghanistan," he said.
-- Kerry, Defense Secretary Chuck Hagel and Gen. Martin Dempsey, chairman of the Joint Chiefs of Staff, are scheduled to appear before the Senate Foreign Relations Committee Tuesday. A senior State Department official said Kerry will argue that failure to act on Syria "unravels the deterrent impact of the international norm against chemical weapons use."
-- The United States must take action against Syria after its alleged chemical weapons use or risk losing credibility in the world, U.S. Sen. John McCain said on CNN's "New Day" Tuesday morning.
-- The Obama administration will conduct classified briefings regarding Syria for Congress almost every day this week, CNN's Dana Bash has learned.
-- Kerry will testify before congressional committees Wednesday, congressional sources said. He will testify to the House Foreign Affairs Committee, while he will join Director of National Intelligence James Clapper in a classified briefing for the Senate Foreign Relations Committee.
-- U.N. Secretary-General Ban Ki-moon said all biomedical and environmental samples gathered by inspectors investigating the alleged chemical weapons attack in Syria "will have arrived at the designated laboratories by tomorrow." Speaking to reporters Tuesday, he said investigators are expediting the review process, but stressed the importance of not jeopardizing scientific timelines needed for accurate analysis.
-- Ban said if confirmed, "the use of chemical weapons by anyone, under any circumstances," would represents a "serious violation of international law" and an "outrageous war crime."
-- Ban called "for its members to unite and develop an appropriate response should the allegations prove to be true." He said the U.N. Security Council "has a duty to move beyond the current stalemate and show leadership."
INTERNATIONAL REACTION, DEVELOPMENTS
-- Syrian Ambassador to the U.N. Bashar Jaafari told CNN's Christiane Amanpour on Tuesday that "allegations" of Syrian government aggression and use of chemical weapons "are false and unfounded."
-- The use of weapons of mass destruction is a "horrible appalling crime" and those who deploy such weapons "should be held accountable," Jaafari said. Syria "has been a victim of intrusion" and "interference" in its domestic life by "foreign intelligence," Jaafari said.
-- Jaafari, defending his country's policies, said that the issue for his country is "about an aggression that will strike the whole Syrian people" and "we are all victims of any escalation of the situation."
-- Amid heightened tension in the region, Israel carried out a missile test Tuesday morning in the Mediterranean. Israel's Ministry of Defense said it and the U.S. Missile Defense Agency "completed a successful flight test (of the) new version of the Sparrow target missile." This is part of a high-altitude ballistic missile defense system capable of defending against a long-range missile attack.
The trial was carried out from an Israeli test range over the Mediterranean Sea, it said. The Arrow defense system successfully detected and tracked the system, Israel's Ministry of Defense added.
-- The U.S. Defense Department confirmed that it "provided technical assistance and support" for Israel's missile test over the Mediterranean Sea on Tuesday. But Pentagon spokesman George Little said the "test had nothing to do with United States consideration of military action to respond" to Syria's alleged chemical weapons attack last month.
-- The Chinese foreign affairs spokesman said China has noted the U.S. claim of chemical weapons evidence and said the United States has briefed China about the situation. But Beijing believes "any action taken by the international community should abide by the purposes and principles of the U.N. charter," foreign affairs spokesman Hong Lei said Monday.
-- Russia says it doesn't buy U.S. claims that the Syrian regime used chemical weapons. "There are no facts, there's only talk about what we know for certain," Russian Foreign Minister Sergey Lavrov said, according to the state-run RIA Novosti news agency. "When we ask for more detailed evidence, they say, 'You know, it's all secret, so we can't show you.' That means that there are no such facts."
-- Russia plans to send a delegation of lawmakers to the United States to meet with members of Congress over Syria, RIA Novosti reported Monday, citing a top parliament member.
CNN's Joe Sterling, Mohammed Jamjoom, Saad Abedine, Mohammed Tawfeeq, Yousuf Basil, Josh Levs, Holly Yan, Dana Bash, Tom Dunlavey, Reza Sayah and Catherine E. Shoichet contributed to this report.