Turkey will allow US warplanes to launch airstrikes against the Islamic State group from Incirlik Air Base in southern Turkey, American officials said Thursday.

Ankara and Washington clinched an agreement after months of negotiations and it was revealed a day after President Barack Obama spoke with his Turkish counterpart Recep Tayyip Erdogan about the conflict.

"Access to Turkish bases such as Incirlik air base will increase the coalition's operational efficiency for such counter-ISIL efforts," a defense official told AFP, speaking on condition of anonymity.

Word of the deal also came as the Turkish military pounded IS militants on the Syrian side of the border, in a drastic escalation of the conflict.

The move marks a significant increase in Turkey's role in the fight against the militants, who have seized large areas of Syria and Iraq.

Turkey shares a 500-mile (800-kilometer) border with Syria, and a section of its southern frontier abuts directly with territory controlled by the IS group.

The United States operates both manned and unmanned aircraft in its bombings of IS targets, but had previously not been permitted to use its facilities on bases in its NATO ally Turkey.

"We have decided to further deepen our cooperation in the fight against ISIL, our common efforts to promote security and stability in Iraq, and our work to bring about a political settlement to the conflict in Syria," said Laura Seal, a Defense Department spokeswoman.

The clash in Syria was the most serious between the Turkish army and IS since the militants began to take swathes of Iraq and Syria right up to the Turkish border from 2013.

It followed the killing of a Turkish soldier by cross-border fire from the fighters.

Another 32 people were killed in a suicide bombing in a Turkish town on the Syrian border Monday that was blamed on IS and sparked an upsurge in violence in Turkey's Kurdish-dominated southeast.

"As allies, we take threats to Turkey's border very seriously," said Seal.

"We remain committed to Turkey's defense and will work with Turkey to deepen our cooperation against the shared threat of terrorism."