Turkish President Recep Tayyip Erdogan gestures as he gives a speech on April 28, 2017 during the Atlantic Council summit in Istanbul.

Turkey and the United States can join forces to turn ISIS’s defacto capital of Raqa in Syria into a “graveyard” for the militants, the Turkish president said on Saturday.

“The huge America, the coalition and Turkey can join hands and turn Raqa into a graveyard for Daesh,” Recep Tayyip Erdogan told an Istanbul meeting, using an alternative name for ISIS.

“They will look for a place for themselves to hide,” he said. Erdogan’s comments come ahead of a meeting with President Donald Trump on May 16 in the United States.

Turkey sees the Kurdish People’s Protection Units (YPG) in Syria as a terrorist group linked to the outlawed Kurdistan Workers’ Party (PKK), which has been waging a deadly insurgency against Ankara since 1984.

But for the United States, the YPG is essential in the fight against the ISIS. Turkey this month announced that it had completed its half-year Euphrates Shield operation in northern Syria against militants and Kurdish militia, although it is keeping a presence to maintain security in towns now under control of pro-Ankara Syrian militia.

Ankara is keen to join any US-led operation to clear Raqa of ISIS militants, but without Syrian Kurdish militia forces.

Erdogan on Saturday said he would present Trump at their meeting next month with the “documents” proving YPG’s links to the PKK, which is designated as a terror group by Ankara and Washington.

“We are telling American friends so as not to take a terror group along with them,” the Turkish leader said. Tensions escalated this week with cross-border clashes between Turkish forces and the YPG near the Syrian border. Turkey fired a barrage of artillery at the YPG, who returned fire with rockets on Turkish outposts on the border.