JERUSALEM — The rival Palestinian factions Hamas and Fatah signed an agreement late Sunday in Cairo that paves the way for elections and a new unity government for the West Bank and the Gaza Strip, officials said.

The Cairo agreement comes three and a half months after a broader reconciliation pact was signed by the leaders of the two factions in Doha, Qatar, and a year after they first reached a unity accord.

The new agreement essentially takes steps to carry out the previous one, particularly the registering of new voters in Gaza and the formation of an interim government. Both are to begin May 27, and Egypt “will follow each party’s commitment to the deal,” according to Fawzi Barhoum, a Hamas spokesman.

The agreement was signed by Azzam al-Ahmad for Fatah, and Musa Abu Marzouq for Hamas at Egyptian intelligence headquarters. Sakher Bseiso, a member of the Fatah Central Committee, and Mohammed Nasser of the Hamas political bureau also attended the negotiating session.

Mahmoud Abbas, president of the Palestinian Authority and leader of the Fatah faction, did not issue a statement or any reaction on Sunday night. But he has repeatedly said the reconciliation process was on ice because Hamas leaders had refused to allow the registration of new voters in Gaza, where officials estimate there are as many as 300,000 who were not signed up for the last election, in 2006.

“Without elections there will be no reconciliation,” Mr. Abbas said in a meeting with a delegation of Americans last Saturday. Mr. Abbas also said then that until the elections, the interim government he had promised to set up would be “transitional, technocratic and independent,” and would not include representatives of Hamas.

“Everybody in the government should recognize Israel, denounce terrorism,” he said. “Hamas is the opposition. If I allow them to be in the government, it will not work.”

The Cairo deal comes days after Mr. Abbas announced a long-awaited reshuffling of the Palestinian Authority cabinet, which kept Salam Fayyad in place as prime minister. Hamas, meanwhile, is in the midst of secret internal elections that stretch over several months, in which Khaled Meshal, the exiled head of the political bureau, is believed to have shored up support.

Mkhaimar Abusada, professor of political science at Al Azhar University in Gaza, said the agreement was an incremental step while both sides wait for political events abroad — Hamas is closely watching the Egyptian elections that start this month to see whether it might have a new Islamist sponsor, and Mr. Abbas is hopeful that a re-elected President Obama might take a more aggressive approach to the Israel-Palestinian conflict.

“The talks are aimed at absorbing Palestinian frustration and pressure for the stalemate of the real reconciliation,” Mr. Abusada said.

One senior Palestinian official in the West Bank, speaking on the condition of anonymity because he was not authorized to comment publicly on the talks, said the promise to allow the Central Election Commission to begin work in Gaza next week was the most substantive and significant component of the agreement.

“If they say now we are supposed to start working on a government of national consensus — we were supposed to start working on a government of national consensus a year ago,” this official noted. “If there is something significant, it will be signed by President Abbas himself.”