(Reuters) - BEIRUT, Aug 27 (Reuters) - The Lebanese army shelled militant positions in the border zone with Syria on Wednesday near a town that was seized by Islamist insurgents earlier this month, a security source said.
It was the first such engagement since the radical Sunni Muslim militants including fighters affiliated to Islamic State withdrew from the town of Arsal three weeks ago following five days of deadly battles with the army.
The army opened fire with artillery after observing suspicious movement by the militants, the source said. There was no immediate information on casualties.
Earlier, Syrian warplanes had bombed the same area, the source said.
The five-day battle in Arsal marked the biggest spillover to date of the Syrian civil war into Lebanon. Dozens of people were killed, including 18 soldiers.
The insurgents including members of the Nusra Front, al Qaeda's official affiliate in the Syrian war, and Islamic State, which has seized swathes of territory in Syria and Iraq.
The militant forces withdrew on Aug. 7, taking with them 18 captive soldiers and 15 policemen.
(Reporting by Tom Perry; Editing by Mark Heinrich)