A Russian military helicopter was shot down by ISIS fighters in Syria, and both pilots were killed, the Russian military said.
Russia's defense ministry said in a statement reported by state media Tass that the Mi-25 helicopter was on a test flight with ammunition near Homs when it responded to help fight an ISIS offensive east of the ancient city of Palmyra.
"After having run out of ammunition, the turning around helicopter was hit by militants' gunfire from the ground and crashed in the area controlled by the Syrian governmental army. The crew died," the defense ministry said in the statement.
In September, the Russians began intervening on behalf of Syrian President Bashar Assad in the government's efforts to fight ISIS. The U.S. and its allies have accused Russia of using warplanes to bomb Assad's moderate enemies instead of focusing on ISIS.
Russian President Vladimir Putin announced in March that he would be withdrawing Russian troops from Syria. Putin declared that the goals of the military had been met.
Russia's airbase in Syria's province of Latakia and a naval facility in the Syrian port of Tartus would continue to operate, Putin said then.
Syrian government forces recaptured Palmyra from ISIS in May.