BEIRUT, Oct 31 (Reuters) - Syrian rebels said on Wednesday they had formed a brigade of sympathetic Palestinians in a Damascus district to fight armed Palestinians aligned with President Bashar al-Assad.

About 150,000 Palestinian refugees live in the Syrian capital's Yarmouk camp, a sprawling area of concrete apartment blocks, where some residents support the 19-month-old uprising against Assad and others fight alongside Syrian soldiers.

"We've been arming Palestinians who are willing to fight ... We have formed Liwa al-Asifah (Storm Brigade) which is made up of Palestinian fighters only," a rebel commander from the Suqour al-Golan (Golan Falcons) brigade told Reuters.

"Its task is to be in charge of the Yarmouk camp. We all support it and back it," he added.

Rebels said they and the new brigade will attack Yarmouk fighters loyal to Ahmed Jibril, head of the Syrian-sponsored Popular Front for the Liberation of Palestine-General Command (PFLP-GC), accusing Jibril's men of harassing camp residents and attacking Free Syrian Army (FSA) fighters.

"Now they are targets for us, targets for all the FSA. All of them with no exceptions," said another Syrian rebel commander who asked not to be named.

Some PFLP-GC fighters had handed their weapons to the rebels, the commander said, calling on others to follow suit and threatening to assassinate pro-Assad figures.

Syria hosts half a million Palestinian refugees, mostly descendants of those admitted after the creation of Israel in 1948, and has always cast itself as a champion of the Palestinian struggle, sponsoring several guerrilla factions.

But Syria's uprising has split Palestinian loyalties, with many joining anti-Assad protests. The Islamist Palestinian Hamas movement closed its offices in Damascus earlier this year.

A bomb exploded early on Wednesday under the car of a Syrian army colonel in Yarmouk, but he was not in the vehicle and there were no casualties, according to the British-based Syrian Observatory for Human Rights, which monitors the conflict.

It was not clear if the incident was related to the tension between Syrian rebels and Palestinian factions in Yarmouk.

More than 180 people were killed in Syria on Tuesday, many of them in government air strikes, the Observatory said.

It estimates that at least 32,000 people have been killed since March 2011 when peaceful protests against Assad's rule erupted. They were violently repressed, leading to a civil war.