Amr Moussa, the Arab League secretary-general, said that direct negotiations should be preceded by "written guarantees" from the United States, particularly on the subject of Israeli settlements.

"We are not against negotiations," Moussa said. "But... we cannot accept talks with no preconditions."

'Decisions to be made'

Moussa said on Thursday that Barack Obama, the US president, sent a letter to Abbas including "some guarantees".

He did not reveal the contents of the letter, however, and said the Arab League had further questions for Obama, which were included in a letter sent to the US embassy in Cairo.

The Palestinian Authority said any final decision about re-entering negotiations would depend on the US response.

"There is a green light from the Arabs to go to direct negotiations if we receive terms of reference... in line with the letter," said Nabil Abu Rdainah, an aide to Abbas.

Mahmoud Abbas, the Palestinian president, travelled to the Egyptian capital on Thursday to discuss the issue with the Arab foreign ministers.

Abbas wants a guarantee that the Israeli government will completely halt settlement construction in occupied east Jerusalem and the West Bank.

Settlement freeze

Israel is currently nearing the end of a 10-month moratorium on new settlement construction in the West Bank, which is set to expire in September.

Binyamin Netanyahu, the Israeli prime minister, warned on Wednesday that his government will collapse if he extends the freeze.

Settlement construction in east Jerusalem continues unabated.

"When I receive written assurances [about] accepting the 1967 borders and halting settlement [building], I will go immediately to the direct talks," Abbas said before the Arab League meeting.

The US state department said Obama would "carefully study" the requests in the Arab League's letter.

"We feel the time is right [for direct talks]," said PJ Crowley, the state department spokesman. "We hope to have these negotiations begin quite soon, but obviously there are still decisions to be made."

Direct talks have been suspended since Israel's three-week war in Gaza began in December 2008.

The Arab League meeting comes the day after Hosni Mubarak, the Egyptian president, and Saudi Arabia's King Abdullah met in Sharm al-Shaikh to discuss the Arab-Israeli "peace process".