The Palestinian quest for an independent state was on the verge of collapse last night after Hamas militants took control of the Gaza Strip, banishing and executing their Fatah rivals and declaring Islamic rule on Israel's doorstep.
Fourteen years after the Oslo accords opened up the prospect of a Palestinian state in the West Bank and Gaza, its putative territory was in danger of breaking into two warring entities as Hamas fighters routed Fatah gunmen at the end of a week of violence that has left almost 100 people, both gunmen and civilians, dead.
Last night Mahmoud Abbas, the Palestinian president and Fatah leader, declared a state of emergency and dissolved the three-month-old "national unity" government as he grasped for a strategy that could undermine the "coup d'etat".
But it was unclear how the president could impose his authority in Gaza - already being called "Hamastan" - where the green flag of the Islamic Resistance movement fluttered on many government buildings in the crowded coastal strip.
"We are telling our people that the past era has ended and will not return," Islam Shahawan, a Hamas spokesman, told the movement's radio station. "The era of justice and Islamic rule have arrived."
Qais Abu Leila, a member of the Palestine Liberation Organisation (PLO) executive committee, said there was determination to take action to stop the "insurrection". "This is a fight to preserve everything that we have built over the last 14 years," he said.
But in Ramallah, the seat of the Palestinian Authority, leaders appeared paralysed as they discussed how to stop the revolt. Some feared the turmoil could lead to the disintegration of the authority. Ominously, Fatah rounded up dozens of Hamas militants in the West Bank, where it is more dominant.
The Bush administration described the Gaza events as "a source of profound concern", accusing Hamas of committing terrorist acts. The EU suspended what few aid projects it still maintains in Gaza. The Arab League warned of a "disastrous outcome" to internecine fighting that has crackled on and off for more than six months.
The Hamas victory is widely seen as a boost for Iran and Syria, which have supported the militants, and a painful reversal for the pro-western regimes in Jordan, Egypt and Saudi Arabia, which worry about Tehran's meddling in Iraq and Lebanon, as well as in the Palestinian Authority.
Jordan also fears that intra-Palestinian fighting could spread from the West Bank and across the river into the kingdom, where at least half the population is of Palestinian origin.
About 25 people were killed and 90 injured in yesterday's violence. Hospital staff said some of the dead had been shot in the head at close range.
Hamas gunmen took over the Palestinian Authority's preventative security and military intelligence headquarters after a three-day siege. Fighters loyal to Mr Abbas retain control of some buildings, but are believed to be short of ammunition.
Sources close to the Palestinian president said Israel had ignored repeated requests to allow deliveries of ammunition to PA forces, leaving them outgunned by Hamas who have relied on smuggled munitions.
Last night Hamas declared it had executed the top Fatah militant in Gaza, Samih al-Madhoun. Witnesses said the conquest of the headquarters of preventative security was followed by a series of executions. One told Associated Press he had seen Hamas men carrying out executions despite pleas from local residents. "They are executing them one by one," he said. "They are carrying one of them on their shoulders, putting him on a sand dune, turning him around and shooting."
The civil war is rooted in a power struggle between Hamas, which won elections last year, and Fatah, the historic core of the PLO. Hamas has refused to formally recognise Israel or renounce violence, triggering international sanctions. It denounces Fatah officials who have negotiated with Israel as renegades and "collaborators".