EREZ BORDER CROSSING, Israel — The militant Islamist group Hamas seized control of most of the Gaza Strip yesterday in coordinated attacks on Palestinian security forces loyal to President Mahmoud Abbas, controlling major roadways and setting up sniper positions atop the territory’s biggest buildings.
By the end of the day, fighters of Mr. Abbas’ secular Fatah faction had been reduced to pockets of resistance in Gaza City, and Hamas issued an ultimatum giving Fatah gunmen 48 hours to lay down their weapons.
At least 24 persons died as Hamas fighters easily overran key Fatah posts, despite recent efforts by the U.S. and its Arab allies to boost Fatah militarily.
In the evening, Mr. Abbas and Prime Minister Ismail Haniyeh of Hamas issued a joint call for an end to the fighting. Hamas immediately denied it constituted a cease-fire.
The unexpectedly swift wave of Hamas victories arguably marks the first successful coup attempt by an Islamist political group in an Arab state.
It raised the specter among Israel, the U.S. and moderate Arab nations that the coastal strip of 1.5 million people is becoming an Islamic fundamentalist mini-state — an entity sometimes referred to as “Hamastan.”
Yesterday’s fighting climaxed a week of battles between Fatah and outnumbered Hamas fighters, who yesterday proved themselves better equipped and better prepared.
“The Fatah guys are running out of ammunition. It’s hard to fight,” said one source familiar with the situation in Gaza. “One battalion in Gaza City had to fall back because they ran out of ammunition.”
In the southern Gaza city of Khan Younis, Hamas operatives reportedly used a tunnel to detonate a bomb under a Fatah security headquarters.
Ehud Yaari, one of Israel best-known commentators, said Fatah’s security forces were caving to Hamas gunmen “like a house of cards.”
Remaining Fatah strongholds consisted of Mr. Abbas’ Gaza City presidential compound, Fatah’s “Sarayah” military headquarters and the Preventive Security headquarters, according to reports from Gaza.
Gaza’s roads were filled with dozens of roadblocks manned by rival militias, though many referred to the coastal strip as having gone “green,” the color symbolic of Islam and Hamas’ banner.
Hamas’ superiority and the collapse of Fatah prompted the U.S. and its allies to speed up consideration of a multinational peacekeeping force along the Gaza-Egypt border.
The European Union’s foreign-policy chief, Javier Solana, said the EU would consider participating in a multinational force if asked. U.N. Secretary-General Ban Ki-moon said he discussed the possible deployment with nations on the Security Council yesterday.
Western support has focused on Mr. Abbas’ Presidential Guard, considered the best-trained and disciplined of the numerous security services and militias loyal to Fatah.
The U.S. this year authorized $59 million to assist the Presidential Guard in training and nonlethal equipment.
On the Israeli side of the Erez Crossing at the northern tip of the Gaza Strip, Palestinians with commercial and medical authorization were both leaving and returning to the strip.
“There are may be 200 checkpoints with masked men and armed men,” said clothing maker Teiysir Bawab, describing the car ride from Gaza City to the border. “At the checkpoints, when they find someone linked with Hamas or Fatah, he is shot.”