BEIRUT (AP) — Syrian troops and allied fighters encircled the last Islamic State-held town on Wednesday after linking up with Iraqi forces, pro-government media and a Syrian opposition monitoring group said.

Al-Manar TV, the media arm of the Lebanese Hezbollah group, said troops have surrounded the eastern town of Boukamal, on the border with Iraq. The Central Military Media Center, an outlet affiliated with the Syrian military, said Syrian troops and allied fighters have begun entering the town. The two outlets said earlier that Syrian troops had linked up with Iraqi forces across the border.

The Britain-based Syrian Observatory for Human Rights said the Iraqi forces entered Syria to help surround the town. Hezbollah and other Iran-backed militias are fighting alongside Syrian troops. The Observatory said government forces are shelling Boukamal from around 15 kilometers (9 miles) away. There was no immediate comment from the Iraqi side.

Boukamal is the last town controlled by IS in Syria and Iraq and was on a key IS supply route. U.S.-backed Syrian forces have been battling IS in the surrounding province of Deir el-Zour, and were believed to be eyeing the town.

Capturing Boukamal would give the Syrian government its first official Iraq border crossing since the frontier region was taken over by insurgents in 2012. IS seized Boukamal and the surrounding area in 2014, when it swept across large parts of Syria and Iraq, capturing several towns and cities.

Last week, Iraqi forces secured the crossing itself, just outside the town, when they drove the militants out of Qaim, on the Iraqi side.

The extremist group's self-styled caliphate is all but gone, but it is expected to continue inspiring and carrying out attacks. The militants still control a number of villages along the border and operate in Syria's vast desert to the west of Deir el-Zour city.