Turkish President Recep Tayyip Erdogan criticized several Arab countries on Friday for endorsing a US-unveiled Middle East strategy, describing it as a “treason.”

“Some Arab countries that support such a plan commit treason against Jerusalem, as well as against their own people, and more importantly against all humanity,” Erdogan said to his party’s lawmakers in the parliament.

On Tuesday, President Donald Trump announced long-awaited outlines of a US proposal to settle the Israeli-Palestinian conflict, warning that it may represent the Palestinians’ last hope at statehood.

Palestinian President Mahmoud Abbas termed it the “slap of the century” peace plan.

Turkey, a strong Palestinian supporter, had opposed the proposal.

“The United States’ so-called peace plan is stillborn,” Turkey’s foreign ministry had said in a statement.

“This is an annexation plan aimed at killing a two-state solution and extorting the Palestinian territory.”

Erdogan today added that, if the situation in the area is not resolved immediately, Turkey may launch a military operation in northwestern Syria’s Idlib province, as attacks by Russian-backed Syrian government forces raised concerns about a new wave of refugees for Turkey.

Speaking in Ankara, Erdogan said Turkey was unable to cope with a fresh migrant influx. Erdogan had said on Wednesday that Ankara was losing patience with the assault and accused Russia of breaching agreements to control conflict in the region.