Syrian border forces on Sunday confronted "terrorists" who had infiltrated from Turkey and killed several of them, the official Syrian state news agency said.
The agency said the incident occurred near a Syrian border post in the province of Latakia. It did not give further details. The two countries share a border around 600 km (400 miles) long.
Turkey said on Sunday one of its military aircraft shot down by Syria on Friday had been attacked without warning, and declared it would formally consult with NATO allies on a reaction. A NATO spokeswoman said envoys from NATO member states would meet on Tuesday.
The shooting down of the aircraft has added a further international dimension to the more than year-long Syrian uprising against President Bashar al-Assad. Turkey, along with Western and Arab countries, has supported the Syrian opposition on the world diplomatic stage.
Turkey is giving shelter to the rebel Free Syria Army and accommodating refugees on its southeastern border with Syria, some 50 km (30 miles) from where the Turkish aircraft was shot down. But it denies providing arms for the insurgents.