The Lebanese army has been deployed to the countrys border with Syria as militants flee areas captured by the Syrian army in the Qalamoun region.
On Monday, the Lebanese army sent commandos to the eastern border to contain the influx of the western-backed militants.
Hundreds of militants have crossed into Lebanon after Syrian forces took control of the strategic town of Yabroud near the Lebanese border.
On Sunday, Syrian troops backed by fighters from Lebanons resistance movement Hezbollah regained control of the key border town.
Lebanon has been rocked by the spillover of the Syrian conflict, with its north being the epicenter of fierce clashes between supporters and opponents of the Syrian government.
Syria has been the scene of deadly violence since March 2011. Over 130,000 people have reportedly been killed and millions displaced due to the turmoil.
According to reports, the Western powers and their regional allies - especially Qatar, Saudi Arabia, and Turkey - are supporting the militants operating inside Syria.