KABUL, Afghanistan (CNN) -- Afghan commandos backed by coalition troops killed 60 militants in a four-day operation in southern Afghanistan and seized an unprecedented amount of narcotics, officials said Saturday.
The operation was in the city of Marjah in Helmand province, where soldiers have been targeting the city's Loy Cherah Bazaar. The bazaar is considered by the U.S. military as the southern region's "militant stronghold and narcotics processing hub."
Afghan and coalition forces launched coordinated air strikes against militant buildings used as drug-making facilities, a joint news release said.
The operation, which started earlier this week, seized about 92,271 kilograms of narcotics.
The haul included 16,850 kilograms of black tar opium, 201 kilograms of processed heroin and 75,000 kilograms of poppy seeds, the release said.
Heroin-processing materials such as ammonium chloride, activated charcoal and soda ash were also found, according to the release.
The combined forces also destroyed bomb-making material, including diesel fuel, improvised explosive device battery systems and homemade explosive materials set for detonation.
"The commandos and their coalition partners relentlessly penetrated an area militants and criminals considered a safe-haven, again proving they will not be denied access to any area in this country," said Col. Greg Julian, a spokesman for the U.S. Forces-Afghanistan.
"The four-day operation severely disrupted one of the key militant and criminal operations, and narcotics hubs in southern Afghanistan," he said.
An unmanned craft was flying over the site to ensure militants do not claim false civilian casualties, according to the release.
Meanwhile, a soldier serving with the International Security Assistance Force was killed in a direct-fire attack in southern Afghanistan, officials said Saturday.
The soldier died Friday, ISAF said. It did not identify the soldier's nationality, but said the victim's next of kin had been notified.
"ISAF mourns the loss of a brave service member who has made the ultimate sacrifice," said Capt. Mark Durkin, a spokesman for ISAF. " I offer our heartfelt condolences to the family and friends of our fallen colleague."
Durkin said the victim "will always be remembered for helping to bring hope and peace to the people of Afghanistan."
The ISAF was formed under a U.N. mandate to bolster a secure environment and support the reconstruction of Afghanistan, according to the organization.
NATO took command in 2003. The force comprises about 50,000 troops from 42 countries, according to the organization.