Syria's air force launched two strikes on the outskirts of Lebanon's frontier town of Arsal on Monday, causing no casualties, a Lebanese security source said.

The raid was the latest in a string of cross-border strikes against Arsal. On January 17, shells rained down on the town, killing eight people, including five children.

A December air raid prompted the Lebanese army to fire back with anti-aircraft guns.

Arsal's residents support the revolt against President Bashar al-Assad, and the town has become home to thousands of Syrians who have fled the conflict.

In a separate development, the Lebanese army said it has detained two Syrian men, including Radwan Mahmud Ayyush, a defector from Syria's army, in the Wadi Hmeid area of Arsal.

"As part of operations to bring the land borders under control, army units in the area of Wadi Hmeid of Arsal detained two men, Omar Mohamed Othman and Radwan Mahmud Ayyush, of Syrian nationality," the army said.

The statement said the two men were detained for "entering Lebanese territory illegally," adding they were being held for questioning.

Ayyush, a former captain in Syria's army, joined his country's rebellion at an unknown date, and became a commander in the opposition's military council in Qusayr, a former rebel stronghold near Lebanon's border.

After a year-long siege, Qusayr fell from rebel hands in June last year after Syrian troops backed by Lebanese Shiite Hezbollah fighters launched a blistering offensive.

Speaking to AFP via the Internet, an opponent from Qusayr said he did not know what role, if any, Ayyush plays today in the rebellion.

Once dominated by Damascus militarily and politically, multi-sectarian Lebanon is deeply divided over the Syrian war, with Sunnis backing the Sunni-led revolt and Shiites largely supporting the Assad regime.

The divisions have widened since Hezbollah acknowledged last May that it was sending fighters into Syria to support Assad's troops.

Third chemical arms shipment leaves Syria
Damascus (AFP) Feb 10, 2014 - A third shipment of chemical weapons material left Syria on Monday under a deal to rid the country of its arsenal by mid-2014, the mission overseeing the operation said.

The joint United Nations-Organisation for the Prohibition of Chemical Weapons (OPCW) mission did not give details about the shipment but said it left on a Norwegian cargo vessel, escorted by ships from four countries.

"The Joint Mission confirms that in-country destruction of some chemical materials has taken place alongside the removal of chemical weapons material, and welcomes progress to date," it said in a statement.

"The Syrian Arab Republic is encouraged to expedite systematic, predictable and high-volume movements to complete the safe removal of chemical materials," it added.

Under a UN resolution that cemented a deal worked out by the United States and Russia, Damascus is to give up all its chemical weapons for destruction by June 30.

But progress has slowed considerably in recent months, and the UN Security Council last week demanded that Syria move faster in the process of dismantling its arsenal of the banned weapons.

Syria has missed several deadlines for removing material, and -- prior to the shipment Monday -- was estimated by Washington to have shipped out just five percent of its stockpile.

Damascus blames the delays on insecurity in the country, where the government is locked in a brutal war with rebels seeking President Bashar al-Assad's overthrow.

But the Security Council last week said "Syria has sufficient material and equipment" as well as "substantial international support" to meet the deadlines.

In a statement, the OPCW's director general Ahmet Uzumcu said he hoped the latest shipment would "generate new momentum" for the operation.

"A significant effort is needed to ensure the chemicals that still remain in Syria are removed -- in accordance with a concrete schedule and without further delay -- consistent with the obligations of the Syrian Arab Republic," he said.

The deal to destroy Syria's chemical arms came after an August 2013 chemical weapons attack on the outskirts of Damascus that reportedly killed hundreds of civilians.

Washington and the opposition blamed the attack on the regime, which has denied responsibility.