ISTANBUL (Reuters) - A car bomb exploded at a checkpoint on the outskirts of the Syrian town of al-Rai near the Turkish border on Tuesday, residents and an emergency worker told Reuters.

The explosion struck a checkpoint some 5 km (3 miles) away from the border, wounding three policemen and four civilians, an emergency worker in the area said.

Turkish broadcaster NTV earlier said the explosion had taken place on the Syrian side of a border crossing about 32 km (20 miles) west of al-Rai.

The town of al-Rai is in an area under the control of Turkey-backed rebels and was seized from Islamic State militants in Ankara’s “Euphrates Shield” operation in 2016.