The Palestinian Fatah-led government has mounted a crackdown on preachers from the rival Hamas movement, arresting or sacking clerics accused of spreading political dissent.

The Fatah campaign, which is being enforced across the West Bank, is a reaction to the violent Hamas takeover of Gaza in June and marks a widening divide between the two factions and territories.

In recent weeks in Nablus, a major Hamas centre of power in the West Bank, police have arrested Sheikh Maher Kharas, a prominent and radical Hamas cleric, and replaced several other clerics who are either members of Hamas or close to the movement, including the head of the province's religious affairs department.

The crackdown follows a wave of arrests of Hamas politicians and the closure of several Hamas-linked charities across the West Bank. It comes at the same time as a new US-backed Fatah security plan for Nablus, in which many common criminals have been rounded up.

Hassan Hilali, the newly installed head of the Waqf - religious affairs department - in Nablus, accused Hamas preachers of using their Friday sermons for political gain. "We are asking the preachers not to change the mosque into something with a political identity, or a certain ideology, or linked to a particular group or cult," he said.

Several clerics had been removed, he said. "Everyone who was in the wrong place lost their job," he said. But he insisted that some of the less hardline Hamas-linked imams remained in their posts.

Mr Hilali has held meetings with local clerics to give them directions on how they should deliver their Friday sermons. In future clerics will have to rotate between mosques every five weeks to prevent them establishing a power base in any one district. "As long as the imam is committed to the law, he will stay in his job," he said.

Before Mr Hilali was appointed the job was held by Sheikh Fayyad al-Akbar, a cleric who had worked in the Waqf department for 25 years and is close to Hamas. He was arrested by the Israeli military in May and held for three months without charge on suspicion of being a Hamas member. When he came out of jail he found he had been sacked.

Mr Akbar said around 15 of the imams in the city and several dozen more across the province had been demoted or replaced. "They were replaced by people close to Fatah and there was no explanation," he said. In one case leaflets passed around the city accused a Hamas cleric of having homosexual affairs.

He said the replacement clerics had been told to recognise the Fatah government in the West Bank as the sole legitimate Palestinian authority, a point bitterly disputed by Hamas, which won elections last year.

"This campaign is just one of many steps they are taking to reduce the popularity of Hamas," said Kholood al-Masri, a Hamas member and the acting deputy mayor of Nablus. "There is a real war against Hamas in the West Bank," she said.

In Gaza Hamas has the upper hand and the Islamist movement has exerted its authority, dominating the mosques as well as the security services. The Hamas takeover in June marked a major military and political defeat for Fatah after a six-month near civil war in Gaza.

Since then Israel and the west have isolated Gaza ever further and refused to talk to the Hamas movement, while they have courted Fatah in the West Bank. Hamas has not been invited to the Middle East peace conference due to be held in the US in late November, while Fatah is hoping that the promise of a return to a substantive peace process will help it regain popularity.

Even those not connected to the two groups are critical of the Fatah mosque campaign. Ziad Othman, a leftwing writer and newspaper columnist who works in the Nablus municipality, said there was still a bitter power struggle under way.

He said the latest campaign showed how much Fatah, traditionally a secular party, now wanted to use the mosque pulpit for political gain. "They are trying to restructure the religious sermons to their own point of view," Othman said. But he said Fatah risked being accused of hypocrisy for seeking political power through religion.