JENIN, West Bank Sept 5 (Reuters) - Gunmen killed a colonel in the Palestinian security forces early on Wednesday when they raked his car with gunfire in the northern West Bank city of Jenin, local officials said.

Hisham al-Rukh was attacked while driving home in the Jenin refugee camp, which has been the focal point of a broad sweep by security forces since May following an upsurge of violence led by criminal gangs and corrupt security officers.

An investigation is being undertaken to find out who is behind this incident, Jenin Governor Talal Dweikat told Palestinian radio after the shooting.

Dweikat's predecessor died of a heart attack after chasing unidentified gunmen who attacked his home in early May. Palestinian officials blamed the attack on criminal gangs, weapons smugglers and former militant leaders whom they suspect of having ties with rogue members of the security forces.

In response to the May attack the Palestinian Authority ordered its elite forces to expand the crackdown beyond Jenin to other West Bank cities and camps.

Wednesday's shooting undermines the campaign and a drive to impose the authority of Palestinian security forces throughout areas under the Authority's control in the occupied West Bank.

Israel largely crushed a Palestinian uprising and campaign of attacks against it in the early years of the past decade through overwhelming military incursions into the West Bank, and especially Jenin.

The Palestinian Authority has struggled to rein in former militant leaders, and the security personnel widely believed to be backing them, following the Israeli withdrawal. (Reporting By Ali Samoudeh in Jenin and Ali Sawafta in Ramallah; Writing by Noah Browning; editing by Crispian Balmer and Jon Boyle)