DAMASCUS - A group of UN observers has reportedly come under fire Tuesday in the focal point city of Homs in central Syria, pro-government al-Ekbaria TV said, adding that one of the UN vehicles was damaged but no casualties were reported.

The TV disclosed no further details.

There has been no immediate confirmation from the UN mission in Syria. But if true, the attack would be the fifth that has targeted UN observers since their arrival last month.

The escalation in violence has undermined the UN efforts to bring the 15-month unrest in Syria to a close.

In another incident Tuesday, Lebanese TVs said 12 Lebanese Shiite pilgrims were kidnapped in Syria's northern Aleppo province by rebel Free Syrian Army.

The latest incident widens the gap and strengthens the sectarian conflict in Syria that has recently spilled over to neighboring Lebanon that has witnessed sectarian clashes over the past days, which resulted in some casualties.

Many Shiites have been kidnapped in Syria by the armed rebels, who are accusing Iran of sending its fighters to help the Syrian regime in stamping out the anti-regime movement in Syria.

Some observers believe that such incidents meant basically to drive wedges between the regional close allies, Syria, Iran and the Lebanese Hezbollah party, thus weakening the ever increasing tide of Shiite influence in the region.

On Monday, the rebel Free Syrian Army has reportedly announced the failure of the six-point peace plan brokered by UN-Arab League joint special envoy Kofi Annan, meaning that they would no longer abide by the plan that calls for a cease-fire and halt of violence from all sides.

Annan is set to visit Syria by the end of this month to follow up on the implementation of his plan, whose prospects are dim given the fact that the unrest in Syria has morphed into a sectarian conflict.