The United States will remain involved in the fight against terrorism in Syria long after the Islamic State (ISIS/ISIL) falls, reportedly envisioned the U.S.-backed Syrian Democratic Forces (SDF), a Kurdish led and dominated group fighting the jihadist group.

Talal Silo, a spokesman for the Kurdish-Arab alliance SDF, told Reuters, “The Americans have strategic interests here [in Syria] after the end of Daesh [ISIS].”

“They [recently] referred to the possibility of securing an area to prepare for a military airport. These are the beginnings – they’re not giving support just to leave. America is not providing all this support for free,” he added, noting, “They have a strategy policy for decades to come. There will be military, economic and political agreements in the long term between the leadership of the northern areas (of Syria) … and the U.S. administration.”

The Pentagon refused to explicitly say how long the United States will stay in Syria.

Eric Pahon, a Pentagon spokesman, told Reuters, “The Department of Defense does not discuss timelines for future operations. However, we remain committed to the destruction of ISIS and preventing its return.”

SDF fighters, led and dominated by the Kurdish People’s Protection Units (YPG), are fighting ISIS in Syria, particularly in and around Raqqa, the terrorist group’s de-facto capital.

There is “still a lot of fighting to do, even after ISIS has been defeated in Raqqa,” Col. Ryan Dillon, a spokesman for the U.S.-led alliance, told Reuters, noting that the jihadist group still holds strongholds in Syria.

“Our mission … is to defeat ISIS in designated areas of Iraq and Syria and to set conditions for follow-on operations to increase regional stability,” added the colonel, without elaborating.

Although U.S.-backed local troops have pushed ISIS out of Mosul, once considered the group’s largest stronghold in Iraq, the terrorist organization still controls territory in the country.

Using data from the American government and the London-based defense research firm IHS Markit, Breitbart News has determined that ISIS still controls about 20 percent of the 35,000 square miles it held at its peak — the beginning of 2015.

YPG is the armed wing of the Democratic Union Party (PYD) that controls large swathes of northern Syria where the U.S.-led coalition has stationed forces.

The PYD has declared the Kurdish-led areas of northern Syrian to be an autonomous region. Syrian dictator Bashar al-Assad, along with his counterparts in Turkey and Iran, reportedly fear that the Kurds within their respective territories may follow in the footsteps of Iraqi Kurdistan and call for an independence, a decision that the former U.S. administrations said lies with the Syrian Kurds.

U.S.-led coalition forces have supported the SDF with air power, artillery, and special forces on the ground.

Support for the YPG has strained the United States’ relationship with its NATO ally Turkey, which considers the militia to be an affiliate of the communist terrorist group Kurdistan Workers Party (PKK).

Both Ankara and Washington continue to consider the PKK a terrorist organization despite the communist group’s efforts against ISIS.  Nevertheless, the United States maintains that the PKK ally is an effective partner against ISIS

Silo, the SDF spokesman, suggested that the United States could establish a base in northern Syria as an alternative to their military facility in Turkey — the Incirlik air base.

The U.S. military already has seven military installations in northern Syria — controlled by the YPG or SDF, revealed the chief of the YPG last month.

Under President Donald Trump, the United States directly provided weapons to the YPG in March ahead of the final offensive to liberate Raqqa, a move that infuriated Turkey.