Egypt's intelligence chief is visiting Washington in what officials say is a push for a more flexible US stance on Hamas, to aid Palestinian unity talks.
The US, EU and UN will not deal with the militant rulers of Gaza unless they reject violence and recognise Israel.
Talks in Cairo to end the rift between Hamas and the Palestinian Authority have faltered over the issue.
The division between the factions is also a major barrier to reconstruction in Gaza after Israel's offensive.
Cairo's influential head of intelligence, Omar Suleiman, is the chief mediator in the talks aimed at forging a Palestinian national unity government.
The US has said it will only deal with a national unity government that includes Hamas if it accepts the conditions.
Respect
FATAH-HAMAS RIVALRY
# January 2006 - Hamas wins Palestinian Authority legislative election
# March 2006 - Hamas government sworn in. US and EU suspend ties
# February-March 2007 - Fatah and Hamas agree to form coalition to end growing factional warfare
# June 2007 - Hamas seizes control of Gaza from Fatah after continued fighting. Unity government dissolved, Israel tightens blockade of Gaza Strip
An unnamed US official told AFP news agency that Mr Suleiman had met US Middle East envoy George Mitchell on Tuesday and might meet Secretary of State Hillary Clinton on Wednesday.
Egyptian and Palestinian officials told AP news agency that Egypt is suggesting the US would accept a commitment from Hamas to "respect" existing Palestinian agreements with Israel, rather than "commit" to them.
The international community wants Hamas to accept existing Palestinian agreements with Israel, such as the Olso accords, in which the Palestine Liberation Organisation (PLO) recognised the right of the state of Israel to exist and renounced violence.
Hamas's charter calls for the destruction of Israel, although the group has also offered a long-term truce if Israel withdraws to its pre-5 June 1967 borders.
Egyptian Foreign Minister Ahmed Abul Gheit is currently in Brussels for talks with officials including European Union foreign policy chief Javier Solana.
Israel and the international community want reconstruction money to be funnelled through the PA.
Israel also wants the PA involved in any agreement to open the crossings into Gaza, which Israel has kept closed to all but basic aid since Hamas consolidated its control of Gaza by force in 2007.
The division between Hamas and PA President Mahmoud Abbas's Fatah faction is deep, including many other issues such as reform of the Palestinian security services and the PLO, and the timing of fresh Palestinian elections.
Factional fighting
A previous unity agreement fell apart after Israel and its international backers refused to deal with Hamas.
Inter-factional fighting in Gaza came to a head in the summer of 2007 when Hamas fighters ousted the pro-Fatah security forces and overthrew PA control.
As well as continued tension, both sides have been accused of conducting politically motivated arrests and the torture of rival faction members.
Egypt revived the call for Palestinian reconciliation talks in November.
However, Hamas withdrew from the talks, complaining that Fatah continued to arrest Hamas members in the West Bank.
A fresh push for reconciliation was launched after Israel's three-week military offensive in Gaza, which ended on 18 January.
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