Beirut, Asharq Al-Awsat—Turkey’s cabinet on Wednesday formally approved a deal to open up the İncirlik Airbase for use by jets from the US-led coalition targeting the Islamic State of Iraq and Syria (ISIS).

According to Reuters, Washington and Ankara have now signed a deal to formally open the airbase, which lies just 68 miles (110 kilometers) north of the Syrian border, for use by coalition jets.

However, Turkish daily Hürriyet reported that Foreign Ministry spokesperson Tanju Bilgiç said neither country had signed any written documents regarding the proposal as of yet.

The move by the Turkish cabinet however opens the door for further official cooperation between both countries to target the extremist group in Syria. Several other Turkish airbases have already been open to coalition jets since last Friday, when Ankara began targeting ISIS for the first time.

Turkish strikes against ISIS were launched following a terror attack last Monday in the southeastern Turkish town of Suruç which killed 32 people. Turkish authorities said the suicide bomber who carried out the attack had links to ISIS and had traveled to Syria earlier in the year.

The launch of the strikes last Friday also coincided with an air campaign by Ankara targeting the Kurdistan Workers Party (PKK) in northern Iraq, in response to a number of recent attacks on Turkish security forces which were either claimed by or linked with the group.

The PKK and other Kurdish separatist groups in Turkey have since the 1980s waged a deadly insurgency campaign in southeastern Turkey calling for autonomy from Ankara, a conflict that has claimed an estimated 40,000 lives.

Peace talks between Ankara and the PKK began in 2013 and a ceasefire was declared but Turkey’s perceived initial inaction against ISIS in Syria and the treatment of Syrian–Kurdish refugees in Turkey have led to recent tensions.

Bilgiç said use of the İncirlik base would be limited to strikes against ISIS that won’t aid Syrian–Kurdish groups, such as the People’s Protection Units (YPG), fighting ISIS in northern Syria.

The airbase “can be used at any moment when considered necessary” by coalition jets, but “support for the YPG is not one of the elements of the agreement,” Bilgiç said in comments carried by Hürriyet.

This contradicts earlier comments from Washington indicating it intends to use the base to support the YPG against ISIS in Syria.

US State Department Spokesperson John Kirby said US use of bases in Turkey would “allow air support to the YPG to be more timely and effective.”

Bilgiç said that as part of the deal with the US, Ankara also reserved the right to restrict some coalition countries with whom it has tense relations from using its bases.

A source from the Turkish prime minister’s office, who requested anonymity, told Asharq Al-Awsat on Wednesday there would be some limits on the use of the base.

The source said the details of the agreement “still need to be worked out between military officials from both countries, and will be referred after that to political leaders” in Washington and Ankara.