Ten European Union foreign ministers have signed an open letter to Tony Blair to urge him to study prospects for an international force to patrol the Palestinian territories, in his new role as Middle East envoy.

"Dear Tony," the letter began, signed by ministers from the EU's Mediterranean countries who met last week in Slovenia. The letter, published in Le Monde, was the brainchild of the French Foreign Minister, Bernard Kouchner.

The ministers argued that it was time to move on from the "failed" road map, the internationally agreed blueprint for peace. They stressed that a "robust international force" should only be considered in the context of a future agreed peace plan, "without being a substitute for one".

The former prime minister's remit was defined by the Quartet which appointed him on 27 June, confining him to promoting Palestinian economic development and advising on building the institutions of a future Palestinian state. The Quartet groups the US, Russia, the UN and the EU.

The letter also urged Mr Blair to push Israel for immediate measures to bolster Palestinian President Mahmoud Abbas, including a mass prisoner release, and called for a reopening of the main crossing points to ease the humanitarian crisis in Hamas-ruled Gaza.

The ministers who signed the document, in addition to France, were from Slovenia, Bulgaria, Cyprus, Spain, Greece, Italy, Malta, Portugal and Romania.