CAIRO, Egypt – As Gaza descends into chaos, the great powers are urging the Palestinian Authority to enforce its pledge to disarm terrorists.

Yesterday, the Palestinian Authority’s ruling Fatah Party announced plans to run a unified slate in the January 25 elections after three of its party offices were seized briefly by gunmen.

With an eye on the upcoming elections, America, the European Union, Russia, and the United Nations issued a statement yesterday specifically asking the Palestine Liberation Organization’s chairman, Mahmoud Abbas, to codify a new law that would prohibit armed groups from pursuing political goals through violence. An Israeli official yesterday told The New York Sun that he expects Hamas, the Islamist terrorist group that is the rival of Fatah, to take at least 40% of the seats in the January 25 elections for the Palestinian Arab parliament. The parliament has power not only in Gaza but also in areas of the West Bank.

But fighting between rival Palestinian Arab factions in Gaza and renewed fighting with Israel may undermine the hopes of outside powers to curb violence. Yesterday, gunmen from Fatah seized three party offices, prompting swift denunciations from the Palestinian Authority’s Interior Ministry. Hours after the men were prompted to leave, the party announced it would be submitting a unified list of candidates for the elections. The party almost split after a Fatah leader jailed by Israel, Marwan Barghouti, announced plans to run an independent list of candidates.

Meanwhile, Israeli battleships and artillery began bombarding positions in northern Gaza after the Israeli air force dropped leaflets warning civilians to vacate the area, which has been used as a staging ground for rocket attacks into Israel. Also yesterday, Israeli jets fired on a command base south of Beirut for the Popular Front for the Liberation of Palestine-General Command in retaliation for rocket attacks into northern Israel.

The president of the Palestinian Authority, Mr. Abbas, yesterday denounced Israel’s military moves. “Israel left the Gaza Strip and has no right to come back,” Reuters quoted Mr. Abbas as saying.

In a statement to the press, the Israel Defense Force said it commenced the bombing “in the absence of any action from the Palestinian Authority to stop terror.” According to Israel’s military, at least 200 Qassam rockets have been fired into southern Israel from Gaza since August. In some instances, those rockets have come close to hitting key infrastructure in the Jewish state, such as a power generator close to the Gaza border.

The latest fighting, however, could presage greater political problems for Mr. Abbas and the Israeli prime minister, Ariel Sharon, who last month formed a new party dedicated to negotiating the borders between Israel and Palestinian Arab-controlled areas. In the last week, Mr. Abbas has threatened to resign over growing splits in his party. While he has pledged to begin disarming terror groups in the territories, he has said he would do so only after the January 25 election.

But the scene in Gaza yesterday suggested that Mr. Abbas was barely in control and that he could not deliver on promises to curb terror. Yesterday, for example, the popular resistance committees and the armed wing of Fatah, known as the al-Aqsa Martyrs Brigade, released a statement vowing to answer the bombardment with more rocket attacks and “isolation with isolation.”

Meanwhile, the Palestinian Authority confirmed that three Britons, including one human rights activist, were kidnapped in Gaza near the Rafah border crossing with Egypt. According to the BBC, the abductees were a man, a woman, and a child. The Associated Press reported: “It was not known who took them, but such abductions are becoming relatively common in Gaza and usually end after a few hours with no one harmed. The kidnappers usually demand jobs or freedom for imprisoned relatives.”

The greatest challenge for Messrs. Sharon and Abbas will be the prospect of Hamas winning a plurality in the January 25 elections. If Hamas wins, it not only could use its influence to prevent its disarming, but possibly bargain for jobs in the Palestinian security services Israel is hoping would help eliminate them.

Earlier this month, Khaled Mishal, the chief of Hamas’s politburo in Damascus, paid a visit to Tehran, where he warned his group would retaliate if Israel took pre-emptive action against Iran’s nuclear program. Iran’s president this fall promised to wipe the Jewish state off the map.

Mr. Sharon has said no Israeli government would negotiate with a government that included an armed Hamas. The House and Senate also have passed resolutions threatening American aid to the Palestinian Authority would be in peril if Hamas was a part of the next Palestinian government, a sentiment hinted at by senior European Union officials as well.