RAMALLAH, May 6 (Reuters) - Masked gunmen shot and killed a Palestinian man they thought was an Israeli collaborator in the occupied West Bank on Friday, medical and security sources said.

Mohammad Khawaldi, 30, was shot in Jalazoun refugee camp near the city of Ramallah, his body riddled with bullets, a medic who transferred the corpse to a hospital told Reuters.

A Palestinian security source said Khawaldi worked for Israeli intelligence and was a wanted man. Palestinian security did not know the identity of the killers and has begun an investigation, the source said.

Government spokesman Ghassan Khatib said the Palestinian Authority was seeking clarification on the killing.

Palestinians look harshly upon collaboration with Israel. During a Palestinian uprising which began in 2000, militants publicly executed people they accused of tipping off the Jewish state about the whereabouts of wanted men.

But such killings have become rare in the West Bank since a bolstered Palestinian police force, supervised by Western-backed Palestinian President Mahmoud Abbas's government, has largely restored law and order in the past few years.

Last month gunmen shot and killed a well-known Arab-Israeli actor in the West Bank town of Jenin.

On Wednesday Gaza's Islamist Hamas government executed a man convicted of collaborating with Israel. Under Palestinian law, executions should be carried out only with presidential approval, but Hamas ignored this.

Wednesday's execution came on the same day that the leaders of Hamas ratified a deal with Abbas to end a Palestinian schism that has left Hamas in sole control of the Gaza Strip.

Hamas defeated Abbas's Fateh Group in a brief civil war in 2007, establishing its own security force in the coastal enclave and leaving Fateh in control of just the West Bank, still under Israeli occupation.

Abbas has refrained from approving death sentences against Palestinians convicted of capital offenses in the West Bank.

(Reporting by Mohammed Assadi and Ali Sawafta; Writing by Maayan Lubell; Editing by Michael Roddy)