Security officials said the soldiers were killed in a four-wheel drive vehicle east of Arsal, a town in northeastern Lebanon.

Since the start of the conflict in Syria, there have been outbreaks of deadly violence on the Lebanese border.

Militants use the Lebanese border to ship arms and other supplies as well as new recruits for their war in Syria. 

Lebanon is increasingly facing the risk of a spillover of the conflict in Syria.

On Monday, three mortar shells fired from Syria killed at least one woman near the eastern Lebanese town of Hermel.

Since the start of the Syria conflict in March 2011, a number of rockets and mortar shells have struck Lebanese territory.

The rebel Free Syrian Army has claimed responsibility for the attacks in at least two occasions.
 

The Syrian army is currently fighting militants in the strategic town of al-Qusayr which lies close to the Lebanese border.

The two-year-old conflict in Syria has already tumbled into Lebanon's Bekaa Valley and exploded into deadly street fighting in its northern city of Tripoli.

"It is hugely alarming. It points to the fact that there are a decreasing number of brakes that can be applied to this situation," said Julien Barnes-Dacey, senior policy fellow at the European Council on Foreign Relations.

"It's spiraling out of control, moving deeper and deeper within Syria but clearly now across Lebanon and the region."

On Monday, EU foreign ministers decided to lift an embargo on arming militants in Syria.
 

Both Lebanon and Syria are on the forefront of a “resistance” against Israel and its expansionist policies in the region.

Israel has seen its myth of invincibility shattered by repeated defeats against the Lebanese national resistance, Hezbollah.