President Donald Trump has "reaffirmed" U.S. support for Turkey in a phone call with President Recep Tayyip Erdogan while urging President Bashar al-Assad's regime, Russia, and Iran to halt their offensive in Syria's northwestern Idlib Province -- the last rebel-held area in northwestern Syria -- the White House said on February 28.
The two talked after 33 Turkish soldiers were killed the previous day in an air strike by Russian-backed Syrian regime forces, triggering a deadly response by Ankara.
Trump "reaffirmed his support for Turkey's efforts to de-escalate the situation in northwest Syria and avoid a humanitarian catastrophe," the White House said, without giving specifics about the support.
Meanwhile, the Turkish presidency said Erdogan and Trump agreed on measures to avoid a "humanitarian tragedy" in Idlib.
"The two leaders agreed on additional steps without delay in order to avert a big humanitarian tragedy unfolding in the Idlib region," it said in a statement.
Erdogan told Trump that Turkey had delivered the necessary response to the perpetrators of the "despicable attack aimed at our heroic soldiers" and reiterated Ankara's determination to clear "regime elements" from areas in Idlib covered by a cease-fire agreement signed by Ankara and Moscow in 2018, the statement said.
A war monitor said Turkish reprisals killed 31 Syrian soldiers in Idlib on February 28.
The retaliatory drone and artillery strikes hit Syrian Army positions in southern and eastern parts of the province that were recaptured by the government in a nearly three-month-old offensive against the rebel enclave, Britain-based Syrian Observatory for Human Rights said.
Syria did not immediately confirm the reported troop deaths.
UN Secretary-General Antonio Guterres said the escalation of fighting was "one of the most alarming moments" of the Syrian war and called for an immediate cease-fire.
Hours after the February 27 strike, Turkey warned it was opening the gates for refugees to flee to Europe, a move that could have major repercussions for its western neighbors, which swiftly moved to boost border security.
Turkey's neighbors Greece and Bulgaria reinforced their borders in response to Ankara's threat to reopen the frontier, shut under an agreement that halted the 2015-16 migration crisis when more than a million people crossed into Europe by foot.