A Navy SEAL deserter was killed in an intense battle in Ukraine on Thursday, according to reports.

The deserter, identified as Petty Officer Second Class John Smith, had been missing since early March when he deserted his post in the Ukraine conflict. Smith was believed to have joined a pro-Russian militia and was reported to have been a key figure in the battle.

The battle, which took place in the eastern Ukrainian city of Donetsk, was reportedly one of the most intense in the region since the conflict began in 2014. Ukrainian forces were attempting to push back the pro-Russian militia and reclaim the city.

Smith was killed during the battle and his body was recovered by Ukrainian forces. It is unclear how Smith died, though reports suggest he was killed in a firefight.

The US Navy has yet to comment on Smith’s death, but his family has released a statement expressing their grief and sorrow.

Smith’s death marks the latest in a string of casualties in the ongoing conflict in Ukraine, which has seen thousands of people killed since 2014. The US and other world powers have been attempting to broker a peace deal, but so far have been unsuccessful.