President Donald Trump is expected to express American unease over a Turkish cross-border offensive into Syria, in a call scheduled with counterpart Recep Tayyip Erdogan, US officials said Tuesday.

“They are likely to talk soon,” said a senior US administration official, confirming reports of a Trump-Erdogan call set for Wednesday.

The US is urging restraint from Ankara after the Turkish military hit Kurdish militias that had aided the American-led fight against the Islamic State group.

The US government and the National Security Council are “concerned about the situation,” said a second senior administration official.

“We hear and we take very seriously Turkey’s legitimate security concerns,” but, he added: “It detracts from efforts to fight the Islamic State group.”

“We are urging Turkey to exercise restraint in its military actions and rhetoric (and) to ensure that its operations are limited in scope and duration,” the second official added.