Attackers hurled a hand grenade and fired rifles at pro-Yasser Arafat (searchdemonstrators in this Palestinian refugee camp in Lebanon (search), injuring 15 people, a Palestinian official said Friday.

 

Col. Khaled Aref (search), a senior official of Arafat's Fatah faction, said three of those injured during a Thursday night march in support of the besieged Palestinian leader were in critically wounded.

No group claimed responsibility for the attack, but Aref blamed it on a rival Muslim group that had previously fought with Arafat loyalists.

About 400 people took to Ein El-Hilweh's narrow alleyways in southern Lebanon upon hearing of Israel's threats to expel Arafat from his West Bank headquarters.

"With our soul, with our blood we redeem you Oh Arafat," the protesters chanted.

When the crowd reached the camp's Safsaf neighborhood, a hotbed of Palestinian Muslim extremists, attackers threw a hand grenade and fired automatic rifles at them. The crowd dispersed after the attack.

Early Friday, the situation was tense with armed Muslim militants on Safsaf street corners and gun-toting Arafat loyalists outside their offices throughout the camp.

Ein El-Hilweh, on the outskirts of the southern port city of Sidon, has been the scene of frequent bombings, assassinations and shootings involving Palestinian factions vying for the camp's control.

Lebanese troops man checkpoints outside the camp, but do not enter.

Aref blamed Thursday's attack on followers of Muslim militant leader Abdullah Shreidi, who died in July from wounds sustained in a May assassination attempt.

Shreidi led the extremist al-Nour faction, an Islamic fundamentalist group that split from the radical Asbat al-Ansar group, which is on the U.S. list of terrorist organizations.

His shooting in May sparked fighting between supporters and Arafat loyalists, killing eight people and wounding about 30 others.

Ein El-Hilweh is home to 75,000 Palestinians displaced by the 1948 creation of Israel and their descendants. It is the largest of 12 Palestinian refugee camps in Lebanon, where about 350,000 Palestinians live.