Turkish President Recep Tayyip Erdoğan said 20 people were killed in the bomb attack in northern Syria on Wednesday, including five U.S. troops.
A U.S. official had earlier told Reuters four U.S. troops had been killed and three wounded in the blast, which an Daesh-affiliated site said was the work of a suicide bomber. Others said only two had been killed.
"The information I have is news pointing toward that there are five U.S. soldiers and 20 died in total," Erdoğan said in a news conference with the Croatian president in Ankara.
The attack appears to be the deadliest on U.S. forces in Syria since they deployed on the ground there in 2015.
Erdoğan said he did not believe the attack in the Syrian town of Manbij would impact U.S. President Donald Trump's decision to withdraw from Syria - "because I saw honourable Trump's determination on this point," he said.
"Suicide attack in Syria's Manbij killing US soldiers could be meant to dissuade US withdrawal from Syria. But I do not believe Trump will lie down in face of bombing attack, as this would be victory for Daesh," Turkish president said in his comments related to the bombing attack.
"Turkey will continue fight against Daesh, to eliminate terrorist group in war-torn Syria," Erdoğan added.
Manbij remains under the control of the PYD/YPG, the Syrian affiliate of the PKK terrorist organization.
During its 30-year terrorist campaign against Turkey, the PKK has taken some 40,000 lives. The PYD/YPG is its Syrian branch.
The attack came after Trump's surprise announcement last month of the withdrawal of American forces from Syria.
The pullout decision came during a phone call with Erdogan in which the two leaders agreed on the need for more effective coordination over the civil war-torn country.
