The Latest on developments in Syria (all times local):

5:45 p.m.

The Islamic State-linked news agency Aamaq has released a video purporting to show two Russian captives who say they have been taken prisoner by the extremists in eastern Syria.

In the video released on social media Tuesday, one of the captured men identifies himself. He says he and his colleague, who appears badly beaten, were captured near al-Shoula, a village outside of Deir el-Zour city, during a counteroffensive by IS in the area.

The speaker doesn't say when the two men were captured. They appear hand-cuffed and are wearing local garb.

The report first emerged last week. At the time, the Russian Defense Ministry denied it, saying no Russian servicemen have been taken prisoner in Deir el-Zour or anywhere in Syria.

The Russian military has been backing a Syrian government offensive in the area since September.


11 a.m.

Russia's military says its airstrikes in eastern Syria this week killed more than 300 Islamic State militants.

Russia has been a major backer of Syria's President Bashar Assad whose government troops have been advancing in the eastern province of Deir el-Zour against IS under the cover of Russian airstrikes.

Meanwhile, the Kurdish-led Syrian Democratic Forces are also marching against the Islamic State group, backed by the U.S.-led coalition.

Russia's Defense Ministry said in a statement early on Tuesday that its airstrikes just outside Deir el-Zour, on the eastern bank of the Euphrates River, killed more than 304 IS fighters and left more than 200 wounded.

The ministry says the airstrikes also hit and destroyed an IS training center, as well artillery positions, tanks and ammunition depots belonging to the militants.