Palestinian President Mahmoud Abbas swore in a Hamas government this evening, handing the Islamic militant group an administration on the brink of financial collapse and fighting isolation.
The ceremony came a day after the centrist Kadima Party of interim Prime Minister Ehud Olmert won Israel's elections on a platform of imposing the Jewish state's final borders with the Palestinians by dismantling remote settlements in the West Bank.
The 24-member Palestinian cabinet is dominated by Hamas loyalists after other factions including Abbas's long-dominant Fatah movement refused to join following the militant group's shock victory in elections in January.
Ministers swore an oath on the Koran against the backdrop of portraits of Abbas and late leader Yasser Arafat.
Those in the West Bank city of Ramallah took part in the ceremony by video-link to Gaza, where Abbas presided over the swearing-in, because of Israeli travel curbs on Hamas officials.
The United States ordered its diplomats and contractors not to have any contacts with Palestinian ministries once the government was sworn in, US officials said.
The directive, distributed to US officials in the region by email, bars them from having contacts with Hamas-appointed government ministers, whether they are members of Hamas or not, as well as with those who work for them, US officials said.
Contacts will still be permitted with Abbas, his personal office and non-Hamas members of the Palestinian parliament.
The United States hopes to sideline Hamas and pressure it to recognise Israel, renounce violence and abide by peace accords. Hamas is branded a terrorist organisation by Washington.
Washington's partners in the "Quartet" of Middle East mediators - the European Union, Russia and the United Nations - have also said Hamas must reform or risk losing aid to the Palestinian Authority.
Hamas has said talks with Israel would be a waste of time and has stepped up rhetoric against the Jewish state since Ismail Haniyeh, the new prime minister, made a conciliatory speech to parliament on Monday.
The group is committed to Israel's destruction.
Threatened aid cuts could make it more difficult for Hamas to pay the salaries of an estimated 140,000 Palestinian Authority workers, including security personnel. Aid groups say a funding crisis could lead to chaos and violence.