Palestinian President Mahmoud Abbas reached a deal with Prime Minister Ismail Haniyeh of Hamas today to form a unity government the Palestinians hope will end their international isolation and revive aid.
But the Hamas Islamist group said it would never recognise Israel, raising immediate questions over whether a unity coalition would satisfy Western demands for lifting sanctions.
Israel's foreign minister responded skeptically to the deal. The United States said it was seeking more details.
"We have finalised the elements of the political agenda of the national unity government ... Hopefully, in the coming few days we will begin forming the government of national unity," Mr Abbas said on Palestine TV with Haniyeh sitting next to him.
Mr Abbas would decree the existing Hamas-led government a caretaker administration within 48 hours, an aide said. Hamas officials said they wanted Haniyeh to head the unity cabinet.
Palestinians hope the creation of a unity administration will lead to the lifting of a Western aid embargo imposed after Hamas took power in March after a surprising win over Mr Abbas's Fatah movement in January elections.
The United States and the European Union have said they would work with such a government only if it met their three conditions for restoring aid - recognising Israel, renouncing violence and accepting past interim peace deals.
The moderate Mr Abbas, in Gaza where he announced the deal, gave no details on the political agenda of the unity government.
Hamas spokesman Sami Abu Zuhri said it would be based on a document the Islamists and Mr Abbas agreed in June, which fell short of Western and Israeli demands.
That document stemmed from a manifesto drafted by Palestinian prisoners in Israeli jails which hinted at recognition of Israel by calling for a Palestinian state on land captured by the Jewish state in the 1967 Middle East war.
But Hamas's own position was unchanged, Abu Zuhri said. "We will never recognise the legitimacy of the occupation," he said, using the Hamas term for Israel.
Israeli Foreign Minister Tzipi Livni said what mattered was whether the unity government met the West's three conditions for restoring aid. She urged the international community not to waver in demanding acceptance of those terms.
British Prime Minister Tony Blair gave a cautious welcome.
"Of course we have to see the details, but potentially this is a highly significant announcement," said a spokesman, citing Blair at the end of a whirlwind tour of the Middle East.
A spokeswoman for the US consulate in Jerusalem said the United States was waiting for more information.
US officials have warned Abbas's Fatah it would be shunned too if it joined a government that did not accept the three conditions laid out when Hamas assumed power.