"At this critical moment we call on all Palestinians to restrain from violence and resolve their differences through peaceful means," the EU's Commissioner for External Relations Benita Ferrero Waldner said in a statement.

The EU's top foreign affairs official Javier Solana also reacted to the unrest, as fresh reports emerged of heavy gun battles between supporters of the rival Hamas and Fatah parties around the presidential compound in Gaza City.

"I wish to reiterate my support for President Abbas and his efforts to overcome the current political crisis for the benefit of all Palestinians," Solana said.

Palestinian President Mahmoud Abbas called on Saturday for early elections, claiming this was the way to resolve the seething internal tensions with Hamas which have paralyzed the Palestinian administration.

Abbas's call prompted fierce protests followed by armed attacks from the ruling Hamas movement, which swept to power in March. Hamas warned Abbas's move could ignite civil war.

EU demands recognition of Israel

Ferrero-Waldner referred also to demands made by the European bloc as part of a joint Middle East peace drive waged by four world powers, known as the Quartet. Its other members are the United Nations, Russia and the United States.

"The EU stands ready to work with a legitimate Palestinian government, that adopts a platform which reflects the Quartet principles," Ferrero-Waldner said.

The Quartet demands that the Palestinians recognize the state of Israel and renounce violence -- a call reinforced by the commissioner in her comments on Sunday.

"Whether this implies a national unity government or elections is an internal matter for the Palestinian people to decide," Ferrero-Waldner added.