Syrian activists say the Islamic State group has seized a key town in central Syria following clashes with President Bashar Assad's forces.

The town of Qaryatain lies southwest of the historic town of Palmyra, which the extremist group seized in May. The capture of Qaryatain, a heavily populated town, allows the IS group to link up areas under its control in and around Palmyra with areas in the eastern countryside of Qalamoun north of Damascus.

The Britain-based Syrian Observatory for Human Rights says the IS group seized the town Thursday after three suicide bombers targeted army checkpoints at the entrance the day before, setting off a fierce battle.

Websites affiliated with the Islamic State group confirmed the militants had taken over Qaryatain.