Turkey's president threatened Wednesday to use force against Syrian government forces if they don't pull back to an earlier cease-fire line in northern Syria by the end of the month.
Recep Tayyip Erdogan's remarks to members of his ruling party followed rare direct clashes Monday between Turkish and Syrian troops inside Syria, which killed several Turkish and Syrian personnel.
Syrian President Bashar Assad's forces have been advancing deeper into the northwestern province of Idlib, the country's last rebel stronghold, since December. Turkey - a strong backer of some of the rebels - has a dozen military observation posts in Idlib province, which borders Turkey.
"If the (Assad) regime does not retreat to areas behind the observations posts, Turkey will be forced to take matters into its own hands," Erdogan said. He said two of the Turkish observation posts are now behind Syrian lines.
The observation posts were set up as part of an agreement reached in 2018 with Russia - a main supporter of Assad - to monitor a cease-fire that has since collapsed.