An accused Taliban fighter from Russia, who was captured in Afghanistan in November 2009, said at the time of his arrest that he was doing “God’s work,” a former American soldier testified on Monday. Irek Hamidullin, a former Soviet tank commander who converted to Islam and was allegedly fighting for the Taliban, is said to be the first military prisoner from Afghanistan to be tried in a U.S. federal court.

Hamidullin, who is believed to be in his 50s, faces 15 criminal charges, including supporting terrorists and committing other firearms offenses during a terrorist attack on an Afghan Border Police base in eastern Afghanistan in November 2009, Reuters reported, adding that Hamidullin was the only survivor among about 30 insurgents after the failed attack.

“He raised his hands and said [in English], ‘Don't kill me, I'm a Russian citizen,’” Todd Marcum, who shot and wounded Hamidullin during the attack, said in the testimony, according to Reuters. “He said he was just doing 'God's work.’”

Marcum, who is now a fishing guide in Huntington, West Virginia, said that Hamidullin, who was compliant when captured, threw down his weapon and surrendered. Following his arrest, Hamidullin was held by the Pentagon in an unidentified Afghan facility for five years, and was later brought to the U.S. to face charges.

Hamidullin, who worked as a tank commander for the Soviet Union in the early 1980s, was indicted by a grand jury in October 2014. According to prosecutors, Hamidullin opened fire on Afghan and U.S. forces with a machine gun after the attack failed.

In addition, Hamidullin is also accused of attempting to destroy a U.S. military aircraft, conspiracy and attempting to kill a U.S. official. If convicted on all counts, Hamidullin could face life in prison.