Rice suggested Thursday that the Bush administration has strong reservations about Abbas' planned union with Islamic militants whom the West labels terrorists, but she would not confirm that U.S. diplomats have warned Abbas that Washington would shun the new government.
Rice said she will reserve judgment until the coalition government is formed and its policies clear. She said she has seen no evidence yet that the government intends to meet international demands to recognize Israel, renounce violence and abide by agreements made by the previous secular Palestinian government.
"Talking about recognizing or not recognizing the government" is premature, Rice said. "There isn't one yet. When there is one, the United States will make a determination."
Rice spoke to newspaper reporters ahead of a Middle East trip that includes a joint meeting with Abbas and Israeli Prime Minister Ehud Olmert. It was the first time she has addressed the deal brokered last week in Saudi Arabia without U.S. help, the AP reports.
The top U.S. diplomat has described that meeting as the first step in what the United States hopes will be reinvigorated peace efforts between the Palestinians and Israelis. The meeting was set last month, before Abbas and Hamas announced a deal that is popular among Palestinians but broadly opposed in Israel.
Peace efforts are "obviously more complicated because of the uncertainties surrounding the national unity government," but there is no reason to delay either the meeting or associated efforts to offer Palestinians a more hopeful future, Rice said.
The planned coalition government is Abbas' attempt to end a political standoff with Hamas that has lasted more than a year, and stop street fighting between Hamas and his Fatah Party that has killed more than 130 Palestinians since May.
Hamas defeated Fatah in parliamentary elections a year ago, setting up an awkward two-headed power structure that has been unable to govern effectively or receive vital international aid.
Abbas was elected separately and retains his office and a stated commitment to bargain with Israel. He has been the only top Palestinian figure with whom the United States and Israel will deal, and both Israeli and U.S. officials are nervous about Abbas' embrace of Hamas.
"We've made our views clear to not just the Palestinian leadership but to Europeans and others, but we're not going to make a judgment here until we have something that's firm."
Rice went to lengths Thursday to praise Abbas' history as a proponent of peace who has long recognized Israel.
"The fact that he accepts those principles, has lived according to them, has many times in the past renounced violence ... makes it I think very important to maintain the links between President Abbas and Israel and between President Abbas and the United States and Israel," Rice said.
The United States, European Union and Israel list Hamas as a terrorist organization and U.S. law forbids direct contact or aid.
As a legal matter, U.S. officials could continue to deal with Abbas, but it is not clear whether he will be able to speak for all Palestinians or deliver any deal on their behalf.
A stagnant peace plan with Israel starts from the premise that the Palestinian government recognizes Israel's right to exist, something Hamas has never overtly accepted.
Abbas had been trying for months to form a coalition between Hamas and Fatah, in hopes such a coalition could persuade the West to end its crippling aid boycott of the Hamas-led government.
In last week's power-sharing talks, Abbas was unable to wrest a clear commitment from Hamas that it will recognize Israel. Instead, he had to settle for the vague promise that Hamas will "respect" previous peace deals with the Jewish state, implying recognition.