Mahmoud Abbas, Palestinian Authority president, on Thursday night dismissed his Hamas-led government and declared a state of emergency, although with little prospect of imposing it in the Gaza Strip after Hamas routed his Fatah loyalists there in the space of a week.

His decrees marked the end of a unity government the two parties formed in March after agreeing in Mecca on a programme to end their factional strife. In the latest round of violence, Hamas gunmen seized almost all the main Gaza bases of security forces that answer to Mr Abbas.

Mr Abbas is expected to name an emergency new government in what could be a prelude to fresh elections, the first since Hamas swept Fatah out of power in January last year. Ismail Haniya, the sacked Hamas prime minister, is based in Gaza.

Battered by an international boycott and internal frictions, the outgoing PA government had already virtually ceased to function.

The US however quickly endorsed the Palestinian president’s decision. Condoleezza Rice, secretary of state, telephoned Mr Abbas shortly before his announcement. She told reporters afterwards that he had exercised his lawful authority.

Hamas nevertheless on Thursday night appeared intent on clinging to political power. “Prime Minister Haniya remains the head of the government even if it was dissolved by the president,” said Sami Abu Zuhri, a Hamas spokesman associated with hardliners in the movement.

Hamas fighters on Thursday captured one of the last Fatah strongholds in the Gaza Strip, herding prisoners from the headquarters of the Preventive Security force and raising their flag at the fortified compound.

“We are telling our people that the past era has ended and will not return,” said Islam Shahawan, a Hamas military spokesman. “The era of justice and Islamic rule has arrived.”

In the more populous West Bank, however, where Mr Abbas issued last night’s decrees, Fatah is more secure. Although Fatah-aligned militias there responded to events in Gaza by seizing Hamas activists, the prospects of an all-out war were slim. The Hamas government was never able to establish its Executive Force militia in a territory that is under Israeli military control and which the Israeli army raids on a nightly basis.

The euphoria of the Hamas gunmen was not reflected elsewhere on Gaza’s deserted streets. The strip’s 1.3m Palestinians have been spectators rather than partisans in a factional conflict beyond their control.

Palestinians were Thursday night blaming not only their warring factions but also the international community for its failure to embrace the peace deal signed in Mecca by easing restrictions on the unity government.

“Hamas wanted to send a message not just to Fatah, but to Israel, to America and the whole region that it is in control,” said a resident of Gaza’s Jabaliya refugee camp, safely home on Thursday from what has become a life-and-death mission to buy food, and trying to make sense of the territory’s latest week of misery.

The violence was less a civil war than it was a factional conflict over division of powers. After Hamas came to power last year, it continued to act like an opposition party, blaming Fatah and its external enemies for its own government’s failings.

Fatah, out of power for the first time, was in post-election denial and acted as if it were still in charge. Fatah officials disparaged the role of the PA government that had formerly been their power base and insisted that real power resided in the security forces that Fatah continued to control.

Fatah officials negotiated with the US and other governments to strengthen the security forces, fostering Hamas fears of a plot to overthrow it.

Since the weekend, Hamas confronted forces controlled by powerful but latterly absentee Fatah commanders but manned for the most part by other ranks whose main concern was to hold a job in poverty-stricken Gaza. Some claimed they had not received orders, equipment or reinforcements in successive waves of clashes with Hamas.

A US spokesman stressed that Lt-Gen Keith Dayton, the US security coordinator, would continue working with “moderate” Palestinian security forces controlled by Mr Abbas.

The Bush administration pushed for the 2006 elections but was shocked at the result that brought Hamas into office. The dismissal of the government is the culmination of US efforts to isolate Hamas, but Mr Abbas has been severely weakened and US ties with its Arab allies have been severely strained as a result.

The US is using the same rhetoric of supporting freedom and democracy, and moderates against extremists, to justify its direct intervention in three serious conflicts in the region - the Palestinian territories, Lebanon and Iraq.

Additional reporting by Guy Dinmore in Washington