One Turkish soldier was killed and three others wounded in clashes Sunday with Islamic State (IS) militants in Syria's Al-Bab region, local media reported, citing military sources.
Turkish troops and their Syrian rebel allies on Saturday entered Al-Bab to drive IS jihadists from the flashpoint northern town, the Syrian Observatory for Human Rights said.
The Turkish army launched an ambitious campaign inside Syria on August 24 codenamed Euphrates Shield to clean its border from IS jihadists and stop the advance of Kurdish militia.
But the clashes in Al-Bab have proved the toughest in the campaign, with Turkish military fatalities surging.
The latest casualty raised the number of Turkish troops killed in the Syria offensive to 67, the private Dogan news agency reported.
The three injured troops were evacuated from Al-Bab and taken to hospitals in
Turkey's Kilis and Gaziantep provinces near the Syrian border.
Al-Bab is the jihadist group's last stronghold in the northern province of Aleppo and is also being targeted by regime forces.
Turkey has suggested that it could turn its sights to Raqa after the Al-Bab operation is complete, with Turkish President Recep Tayyip Erdogan discussing both Al-Bab and Raqa in a call with US President Donald Trump this week.
Deputy Prime Minister Numan Kurtulmus said on Friday Turkey's Euphrates Shield would "reach its goal" if Al-Bab was captured from IS group.
"Raqa is another issue. Raqa is not something that threatens Turkey's borders," he was quoted as saying in Turkish media.