BEIRUT — The Islamic State group called on young men to take up arms in eastern Syria, where government forces are on the march as the extremists who are under pressure there and in Iraq.

In a statement distributed in Deir el-Zour province that borders Iraq, IS called on all men between 20 and 30 who are able to fight to head to mobilization offices within a week.

The call comes as the extremists have lost large parts of areas they once controlled in Iraq and Syria, where they declared a caliphate in 2014.

Syrian government forces are on the march toward the Deir el-Zour province after capturing areas from IS in the northern province of Raqqa and the central province of Homs. U.S.-backed fighters of the Syrian Democratic Forces are marching inside the group’s de facto capital of Raqqa.

In neighboring Iraq, IS recently lost the northern city of Mosul, the largest urban area they ever held. Iraqi forces now control large parts of northern Iraq where the extremists once held sway.

“They have suffered large setbacks and defeats,” said Omar Abu Laila, a Europe-based opposition activist from Deir el-Zour. He added that preachers are expected to urge young men to join and fight for IS during their Friday sermons.

The group has in the past called on young men to carry arms but this is the first time that they say all young men should join and those who don’t will be punished.

The statement, obtained by The Associated Press from activists in eastern Syria, warns that those who do not join will be undergo questioning and possibly be punished.