Russell Bentley, an American who fought against Ukrainian forces, is missing in the Russian-controlled Donetsk region in eastern Ukraine, police there said Friday, adding that a search was underway.

Bentley went missing on April 8, according to police. The online news outlet Mash said he had disappeared after a district in the city of Donetsk was shelled by Ukrainian forces.

Mash cited his wife as saying he had gone to see if anyone needed help but had not returned. She was quoted as saying she had found his car with his baseball cap in it along with his smashed mobile phone and a pair of glasses.

Bentley, 64, is a self-declared supporter of Russian-backed forces in Ukraine.

He joined pro-Russian fighters in eastern Ukraine in 2014 and used the military call-sign "Texas," the Russian state news agency RIA reported.

It said Bentley had later swapped his gun for journalism and had worked with the Sputnik news agency, another state-owned entity, and obtained Russian citizenship.

Russian state media have described Bentley as a war correspondent.

In 2022, Rolling Stonemagazine ran an interview with Bentley titled "The Bizarre Story of How a Hardcore Texas Leftist Became a Front-line Putin propagandist."