KIEV (Reuters) - Ukraine’s security service said on Friday it had detained the deputy of Abu Omar al-Shishani, the man the Pentagon described as Islamic State’s “minister of war”, after he crossed into Ukraine on a fake passport last year.

The SBU security service said it had taken into custody Al Bara Shishani, a Georgian citizen, in a joint operation with Georgia’s Interior Ministry and the U.S. Central Intelligence Agency (CIA).

An SBU statement said an examination of a photograph of Al Bara Shishani in the agency’s possession “proved that the detained foreigner is indeed a wanted leader of Islamic State”.

Georgia’s state security service confirmed Al Bara Shishani was being held in Ukraine. “Yes, we can confirm this fact ... His (birth) name is Cezar Tokhosashvili,” said Vika Klimicheva, a spokeswoman for the state security service.

He joined Islamic State in 2015 and was the deputy to Abu Omar al-Shishani, who was killed in combat in 2016 and ranked among America’s most wanted militants under a U.S. program that offered up to $5 million for information to help remove him from the battlefield.

Both men were born in Georgia’s mountainous Pankisi gorge region.

After his death, Al Bara Shishani crossed into Turkey and later Ukraine where he continued to coordinate the activities of Islamic State, the SBU statement said.

He was detained in the Kiev region near a private home where he resided, it added, without giving the date of the arrest.