U.S. forces and their allies staged 31 air strikes on Friday inside Syria and Iraq against the militant group Islamic State in Iraq and the Levant (ISIL), according to the U.S.-led task force overseeing the strikes.

Fighters, bombers and remotely controlled aircraft hit 16 targets in Syria while 15 strikes were carried out in Iraq, a Combined Joint Task Force statement said.

The United States and members of the anti-ISIL coalition have been lobbing air strikes into the region since August, following the armed group's encroachment on Iraqi territory. The U.S. became more involved in the conflict after ISIL started beheading American hostages, beginning with journalist James Foley.

The United States and other coalition partners – including Western states such as the United Kingdom and regional powers such as Saudi Arabia – have conducted approximately 1,400 air strikes against ISIL in both Iraq and Syria. However, the Arab states in the coalition have largely limited their efforts to defeating ISIL in Syria, leaving the Western powers to beat back the fighters in Iraq on their own.

Friday's 16 strikes on ISIL in Syria were concentrated on an area near the city of Kobane and destroyed buildings, a staging area and several fighting positions. Two large ISIL units and four tactical units also were hit.

Kobane, which rests close to Syria's border with Turkey, has become a critical battleground. ISIL has repeatedly attempted to seize control of the city, but it has managed to wrest only half of it from local Kurdish forces.

Syria's air force also carried out strikes on ISIL-controlled areas within the country on Thursday. Dozens of civilians were killed and some 175 wounded when aircraft bombed a northern Syrian city controlled by ISIL, residents and a monitoring group said on Friday.

The Syrian Observatory for Human Rights said 37 civilians were killed. The British-based group, which gathers information from a variety of sources, said there has been an increase in air raids by the Syrian military across rebel-held areas in the last three days. It said at least 110 civilians had been killed in more than 470 air strikes on rebel held areas in Syria in the last 72 hours, including towns in insurgent-held eastern suburbs of the capital Damascus, where the army has stepped up a two-year campaign to retake the area.

In Iraq, 15 U.S.-led air strikes hit near Al Asad, Sinjar, Mosul, Al Qaim, Baiji, Kirkuk and Tal Afar, destroying or damaging a rocket system, vehicles, tactical units and fighting positions, the statement said.

Days earlier, on December 18, another airstrike killed the ISIL-appointed governor of Mosul, an Iraqi city controlled by the fighter group. Kurdish fighters on the ground in Iraq seemed to have gained the advantage over ISIL this week, having recaptured several villages.

U.S. Central Command on Friday also released video of an air strike it had conducted within Syria on December 21. The footage shows what U.S. forces identified as "three ISIL buildings" being destroyed in an area near Aleppo, Syria.

Al Jazeera and Reuters