Lebanese army troops carried out house raids Saturday in search for assailants who tossed hand grenades into the northern city of Tripoli, amid fears violence could spread to the Palestinian refugee camp of Ain el-Hilweh and to the eastern Bekaa Valley.

Tension continued to prevail in Tripoli after unidentified assailants tossed two hand grenades into the Bab al-Tabbaneh neighborhood overnight.

Two more hand grenades were tossed into the same area at dawn Saturday, according to press reports. No casualties were reported.

Meanwhile, tension heightened at the Ain el-Hilweh refugee camp near the southern port city of Sidon following reports that two Fatah members were killed in overnight violence.

A cabinet source, on the other hand, feared that the spate of bloody violence in Tripoli could spread to Ain el-Hilweh and the Bekaa.

He cited the infiltration of extremist groups to Tripoli, Ain el-Hilweh and to some areas of the Bekaa as well as the flow of money and arms as good reasons to believe so.

The source said Lebanese authorities were monitoring the flow of arms without being able to act due to the sharp political divide.

Tripoli has been rocked by deadly violence in recent months.

14 people were killed and at least 40 wounded when a bomb blast targeting a bus carrying mostly off-duty Lebanese army soliders went off in Tripoli on Wednesday.

In June and July, 23 people were killed in battles between gunmen of the Sunni Muslim neighborhood of Bab al-Tabbaneh and rivals from the mainly Alawite community allied with Hizbullah in Jabal Mohsen.

There has been tension between the two communities ever since Lebanon's 1975-1990 civil war. Alawites are an offshoot of Shiite Islam and straddle the border into Syria whose President Bashar al-Assad is a follower of the faith.