BEIRUT (AP) — A Free Syrian Army faction seized control of the Syrian side of a major Syria-Iraq border crossing from the Islamic State group Friday night, as IS fighters engaged government forces in the center of the country, killing at least 15 soldiers.

The Local Coordination Committees' network of opposition activists in Syria reported Saturday that fighters belonging to the FSA Southern Front and reportedly supported by the United States killed one IS fighter and injured several others in the process of taking the Tanaf border crossing.

According to the Britain-based Syrian Observatory for Human Rights, the FSA fighters crossed into Syria from Jordan to launch the attack.

The IS-affiliated Aamaq News Agency denied the reports. The IS group had controlled the crossing, located in Homs province in southeast Syria, since government forces withdrew in May 2015.

IS fighters meanwhile attacked the government's supply route to the contested northern city of Aleppo killing between 15 and 20 soldiers, according to various reports. Government forces repelled the attack and secured the road, according to the Observatory and SANA, the Syrian state news agency.

SANA reported government forces killed dozens of IS fighters in the clashes.