TORONTO - The last Western detainee held at the U.S. military prison in Guantanamo Bay returned to Canada on Saturday after a decade in custody following his capture in Afghanistan at age 15 after being wounded in a firefight with U.S. soldiers, officials said.

Canadian Public Safety Minister Vic Toews said that Omar Khadr, 26, arrived at a Canadian military base on a U.S. government plane early Saturday and was transferred to the Millhaven maximum-security prison in Bath, Ontario.

The son of an alleged al-Qaeda financier, Khadr pleaded guilty in 2010 to killing a U.S. soldier in Afghanistan and was eligible to return to Canada from Guantanamo Bay last October under terms of a plea deal. But Canadian Prime Minister Stephen Harper's Conservative government had long refused to request the return of Khadr, the youngest detainee held at Guantanamo. The reluctance was partly due to suspicions about the Khadrs, who have been called "the first family of terrorism."

The U.S. Defense Department confirmed the transfer in a statement and said 166 detainees remain in detention at Guantanamo Bay.

The Toronto-born Khadr was 15 when he was captured in 2002 in Afghanistan, and sent to the Guantanamo prison set up on the U.S. naval base in Cuba to hold suspected terrorists after the Sept. 11, 2001, attacks. He received an eight-year sentence in 2010 after being convicted of throwing a grenade that killed Army Sgt. 1st Class Christopher Speer.

"His head is spinning a bit and it's going to be a real adjustment for him, but at the same time he is so happy to be home," John Norris, Khadr's Canadian lawyer, said after speaking with his client.

Norris said Khadr would be eligible for parole as early as the summer of 2013. He said Khadr's return to Canada comes 10 years too late.

Toews said the U.S. government initiated Khadr's transfer and suggested that Canada had little choice but to accept him because he is a Canadian citizen. It will be up to Canada's national parole board to release him, Toews said.

U.S. Defense Secretary Leon Panetta said in Ottawa this year that sending Khadr back to Canada would be an important step because it would serve as an example to other detainees who are looking to return to their home countries or other places. Some Guantanamo detainees have been reluctant to agree to plea deals after noting that Khadr had remained in Guantanamo even after being eligible to leave.