The Lebanese Army deployed heavily along the northeastern border Thursday as Syrian rebel groups launched an offensive to retake key Syrian towns, leading to intense clashes with Hezbollah-backed regime forces, a security source said.

Speaking to The Daily Star on condition of anonymity, the source said rebel groups were advancing from a range of barren hills toward the Syrian towns of Jousieh and Qusair.

Led by Hezbollah fighters, the Syrian Army said in June of last year it took back the town of Qusair which rebels had held for more than a year. […]