The European Union is extremely concerned by the resignation of Palestinian Prime Minister Mahmoud Abbas, Italian foreign minister Mr Franco Frattini said today.
Speaking at a meeting of EU foreign ministers, Mr Frattini said the 15-nation bloc was "deeply worried by the serious risk of dangerous instability at the head of the Palestinian executive".
The ministers earlier discussed ways of reining in the Palestinian militant group Hamas following its claim of responsibility for a suicide bomb attack in Jerusalem which ended the truce declared by several militant groups.
Danish foreign minister Per Stig Moeller, one of the original architects of the road map, said Abbas's resignation would be a severe setback for the peace process.
"It is deeply serious and does certainly not promote the peace process," Mr Moeller told reporters. "It is a setback if the man the world trusts resigns. I hope he stays and gets decent conditions to work under."
He said it was imperative for the Quartet - the mediation group made up of the United States, European Union, Russia and the United Nations - to meet the Palestinians and the Israelis.
Italy, which holds the rotating EU presidency, says it wants the Quartet to meet in New York on September 22nd.
Diplomats said that in their talks on Hamas, ministers might stop short of adding its political wing to their blacklist of banned terrorist organisations, which would lead to EU states freezing its assets and possibly prosecuting its activists.
The bloc blacklisted Hamas's military wing, the Izz el-Deen al-Qassam Brigades, last year, but is divided over whether to ban the political wing, France arguing it could play a role in peace efforts and provides social services to Palestinians.