ISTANBUL — Turkey deployed F-16 fighter jets against government forces in northwestern Syria on Monday, a sharp escalation of the conflict there after six Turkish soldiers were killed by artillery strikes.
President Recep Tayyip Erdogan of Turkey said that as many as 35 Syrian troops had been “neutralized.” The Syrian Observatory for Human Rights, a monitoring group based in Britain, said the number killed was at least 13.
The Turkish leader also warned Russia, which backs the Syrian government and which controls the airspace in western Syria, not to prevent Turkey from retaliating.
“It should be out of discussion to block us,” Mr. Erdogan said, before leaving for a trip to Ukraine. Describing the dead Turkish soldiers as martyrs, he added that, “It is not possible for us to keep silent” as long as his country’s troops were being targeted.
Syrian government forces have recently intensified their offensive in Idlib, in western Syria, the last rebel-held province. Turkey deployed several hundred troops to observation posts there in 2018, as part of an agreement with Russia to create a de-escalation zone in the area.
But Russian and Syrian forces have been conducting an offensive on the major highway through the province, prompting hundreds of thousands of civilians to flee north toward the border with Turkey.
Turkey has already taken in millions of people trying to escape the war, which started nearly nine years ago, and is concerned that the Syrian push into the area will create a fresh surge of refugees.
The deployment of air power came after the Turkish Defense Ministry said that a supply convoy bringing reinforcements into the observation posts on Monday had come under fire, leaving six Turkish soldiers dead and several others wounded.
The movement of the convoy had been coordinated beforehand, the statement said, and Turkish forces retaliated immediately. “Those who test Turkey’s determination with such heinous attacks will understand they have made a huge mistake,’’ Mr. Erdogan said.
Hwaida Saad contributed reporting from Beirut, Lebanon.