Islamabad, Pakistan (CNN) -- A long-time Red Cross staffer has been killed by his kidnappers in Pakistan, the International Committee of the Red Cross and British government said Sunday.
Khalil Rasjed Dale, 60, was seized in Pakistan's volatile southwestern province of Balochistan in January.
His body was discovered Sunday, and he appears to have been killed recently, ICRC spokesman Sean Maguire said.
Maguire acknowledged Pakistani press reports that Dale had been beheaded but declined to go into details about how he was killed, saying only: "It was a brutal murder that has left us appalled."
The ICRC has identified Dale's body and will be able to bring it home to Britain, Maguire said.
"We were in touch with the abductors a number of times during Khalil's captivity," he said. "We have called upon the Pakistani authorities to conduct a full and immediate investigation into the murder."
"We are not going to talk about who may or may not be responsible for the killing," he added.
The head of the ICRC, Yves Daccord, condemned Dale's killing as a "barbaric act," and said staff members of the international agency were "devastated."
British Foreign Secretary William Hague said the killing was "a senseless and cruel act, targeting someone whose role was to help the people of Pakistan, and causing immeasurable pain to those who knew Mr. Dale."
British Prime Minister David Cameron said he was "deeply saddened" by reports of Dale's death, noting that he died while "providing humanitarian support to others."
"This was a shocking and merciless act, carried out by people with no respect for human life and the rule of law," Cameron said. "Khalil Dale has dedicated many years of his life to helping some of the most vulnerable people in the world and my thoughts today are with his friends and family."
Dale, a nurse who was managing a health program for the ICRC, was seized by armed men in the city of Quetta, near the Afghan border, the Red Cross said in January.
He was on his way home from work in a clearly marked ICRC vehicle and was just 200 yards from a Red Cross residence when he was abducted, the statement said.
The kidnappers released the man's driver, said Nazir Kurd, a senior police official who described Dale as a Yemeni-born British national.
Dale worked for the ICRC and the British Red Cross for many years, carrying out assignments in Somalia, Afghanistan and Iraq, the ICRC said Sunday.
He had been working in Pakistan for almost a year.
"Despite the incident, the ICRC will be continuing its humanitarian work in Pakistan," the Red Cross said at the time of the kidnapping.
CNN's Richard Allen Greene in London and Shaan Khan in Islamabad, Pakistan contributed to this report.