The US has cancelled talks in which ministers had been expected to approve urgent measures leading to the payment of Palestinian salaries, including those of the security forces, which were frozen after a Hamas government came to power.

A European diplomat said the move reinforced fears that the US was intent on "regime change" in the Palestinian-ruled territories. Tensions between Hamas and Fatah forces in Gaza and the West Bank have been exacerbated by the aid freeze by countries who continue to brand Hamas a terrorist group.

"At best it's a delaying tactic, at worst it's an attempt to scupper the entire mechanism," said the diplomat. "The Americans are into regime change. They want the Palestinian Authority to fail."

Western diplomats said a teleconference of the ministers of the Quartet (US, Russian Federation, EU and UN) had been scheduled for Wednesday, after the main powers considered proposals discussed in Brussels last week on the funding mechanism for the PA that would bypass Hamas.

The US envoy to the Middle East, David Welch, said there was "no basis" for talks if they included payment for the security forces.

Salaries have not been paid to Palestinian civil servants since January, and the EU has been urgently trying to work out a payment system that would ease the humanitarian crisis in the Palestinian territories.

The US has stopped aid being channelled through Arab banks by warning them of possible penalties. Some diplomats fear that US policy aims to undermine the Hamas government to such an extent that the Palestinian President, Mahmoud Abbas, would call new elections in the hope that Hamas loses.