Syria's war is almost over and experts say the U.S. has few options to counter what's been a major victory for Russia, Iran and President Bashar al-Assad.
The Syrian military's Fifth Assault Corps, known as "ISIS Hunters," has made ISIS an offer it can't refuse.
In the video, a man identifies himself and a companion as Russian soldiers captured by ISIS during a counteroffensive against Syrian troops in Deir Ezzor.
Two rivals are battling ISIS in the jihadists' final stronghold of Deir ez-Zor. One seeks to return Syria to its former self; the other wants more power for Kurds.
Russian and U.S. allies are battling insurgents and jihadists trying to topple the Syrian government, but the latter wants to reshape the nation.