Maksim LEvin carries a cat near the line of separation from Russian-backed separatists in Donetsk region. File / Reuters

"He went missing in the conflict area on March 13 in the Kyiv region. His body was found near the village of Guta Mezhygirska on April 1," presidential aide Andriy Yermak said on Telegram.

Ukraine's General Prosecutor's Office confirmed Levin had been found dead and said he had been killed by Russian soldiers.

"According to preliminary information, unarmed Maxim Levin was killed by servicemen of the Russian Armed Forces with two shots from small fire arms," it said in a statement on Telegram. "The occupiers killed a Ukrainian photo-journalist."

It said Levin had "disappeared" in March, while covering the war with Russia. An investigation had been opened for "violation of the laws and customs of war" and to determine the exact circumstances of Levin's death.

"Prosecutors of the Kyiv region continue to document all crimes of the aggressor country in order to bring the perpetrators to justice," it said.

The NGO Reporters Without Borders, which works to protect journalists, said on Twitter that Levin was the sixth journalist killed in Ukraine since Russia invaded late in February.

"He was unarmed and wearing a press jacket," it said. "Targeting journalists is a war crime." On March 22, it voiced concern after Levin's disappearance.

The 40-year-old father of four had been working with Ukrainian and international media.

During fighting between Ukrainian forces and Russia-backed separatists in eastern Ukraine in 2014, he managed to escape encirclement in a town where hundreds of Ukrainian soldiers were killed.

Agence France-Presse