ANKARA, Turkey — After nearly 10 months of negotiations, over how best to fight an emerging jihadist group in Syria and Iraq, NATO allies Turkey and the United States have agreed to cooperate on fighting ISIS jihadists in Syria and Iraq, and are also discussing ways to broaden their alliance.

Ankara and Washington agreed to clear ISIS extremists out of an area 98 kilometers by 45 kilometers between two critical Syrian towns of the militants belonging to the jihadist Islamic State of Iraq and the Levant (ISIL) and to turn that area over to coalition-friendly groups that are also fighting Syrian President Bashar al-Assad’s regime. The groups to fill in the area remain to be vetted jointly by Turkey and the US.

Military preparations are underway for further attacks on ISIS strongholds in Syria and Iraq, both neighboring Turkey, from a strategic air base in southern Turkey.

Both US and Turkish aircraft would strike participate in attacks against ISIS targets, Turkish officials said. The US aircraft also are allowed to use three other air bases in Batman, Diyarbakir and Malatya in southeastern Turkey. 

To augment the allied fight against ISIS, 26 US jets from the 480th Fleet, four armed drones and surveillance aircraft would will be deployed at the Turkish bases. The campaign could also be supported by aerial search-and-rescue platforms.

"This is the beginning of a new understanding of military cooperation between the NATO allies," a senior Turkish diplomat for security said. "We have been able to bridge many of our differences regarding what needs to be done [against ISIS] and how."

ISIS has captured large swaths of land in Syria and Iraq since the summer of 2014. Initially reluctant, Turkey has joined the coalition campaign against the group after an ISIS suicide bomber killed 33 people in a small Turkish town on Turkey’s border with Syria July 20, and killed one military officer the next day.

One senior military official said that the military advised the Turkish government to counter any threat from ISIS "in cooperation with the international coalition fighting the group."

"We cautioned the government about potential repercussions of unilateral action in uncharted territory," he said. "Full international legitimacy must be a sine qua non for any operation in a neighboring country."

In a video it released Aug. 18, ISIS threatened Turkey by calling for the "conquest [by jihadists] of Istanbul," Turkey's biggest city.

A diplomat from a NATO member state said that efficient Turkish-US cooperation in the fight against ISIS would maximize chances for success and minimize the length of total operation time necessary to counter the group. 

"We are pleased of this emerging opportunity that will no doubt boost allied operational and logistical capabilities and firepower," he said.

Could the new US-Turkish cooperation be reflected in Turkish procurement programs for which US manufacturers are bidding? "That remains to be seen," said one procurement official. "Too premature to tell."

But an Ankara-based analyst said smoother cooperation between Ankara and Washington during the campaign could inevitably bring the two militaries closer and lure Turkish generals into US systems and solutions.

"That can be one uncalculated side effect of fighting against a common enemy," he said.