Palestinian President Mahmoud Abbas and Israeli Prime Minister Ehud Olmert held an unscheduled meeting Sunday, just days before Abbas travels to Washington for meetings with U.S. leaders, as resurgent violence in the Gaza Strip highlighted Hamas' potential role as a peacemaking spoiler.

The intention appeared to be to keep the meeting at Olmert's official residence a secret. In the past, their frequent sessions have been announced well in advance, and news photographers are granted some access. Sunday's meeting was confirmed only hours before it took place, and then only after The Associated Press queried officials. The two met just last week.

Abbas is due to meet U.S. President George W. Bush in Washington in April 23, and an Israeli official would say only that the meeting was meant to "coordinate" peace moves before the trip.

He would not elaborate, speaking on condition of anonymity because the meeting's agenda was confidential.

Palestinian negotiator Saeb Erekat said Abbas asked Olmert to agree to an Egyptian initiative to arrange an unofficial cease-fire in Gaza, but Olmert gave no commitment. Israel refuses to deal with Hamas. Erekat said the meeting took place Sunday because Abbas was leaving Monday on the trip that will take him to the U.S.

Months of meetings at various levels have failed to produce noticeable progress toward a peace deal.

Israel and the Palestinians renewed negotiations in November at a U.S.-hosted conference in Annapolis, Maryland, ending a seven-year impasse. The talks have been troubled by Palestinian militant attacks, by ongoing Israeli construction and military operations in the West Bank, and by the fact that Islamic Hamas militants rule Gaza. Abbas controls only the West Bank.

The U.S. has been pressuring Israel to ease travel restrictions in the West Bank and give more authority to Palestinian security forces there, so Abbas can point to concrete benefits from peacemaking.

The Palestinians say the Israeli restrictions humiliate them and cripple their economy. Israel says its security measures are vital to prevent Palestinian attacks and that Abbas' security forces are not yet ready to take control.

In Hamas-ruled Gaza, violence spiked after a monthlong lull.

On Sunday an explosion in a Gaza house killed three people and wounded seven, Palestinian officials said. Residents said it was caused by explosives that went off prematurely.

Later Sunday, a Palestinian was wounded in an Israeli airstrike on a house in Gaza City, Palestinians and the Israeli military said.

Last week, militants attacked the Israeli border terminal that pipes the only fuel that reaches Gaza, killing two workers. Israel immediately shut down the terminal and launched raids that have killed 16 people since, including at least six civilians.

Palestinians have warned of a looming fuel shortage, and the director of the territory's only power plant has said it would have to be shut down this week because its fuel would run out.

Israeli officials said Sunday that the fuel terminal was closed to allow authorities to investigate how the gunmen penetrated the compound. Zeev Boim, an Israeli Cabinet minister, said Sunday it would be reopened within days and called the complaints from Hamas about a fuel crisis "absurd."

"What audacity to carry out an attack on the fuel depot ... and then talk about a humanitarian crisis," Boim said.

Also Sunday, Hamas announced it will hold its own commemoration of the 60th anniversary of "al-Naqba," as Palestinians call the creation of the state of Israel, next month. Abbas' government in the West Bank is planning a separate ceremony.

About 700,000 Palestinians fled or were driven from their homes during the two-year war that followed Israel's creation. Palestinians insist that the refugees and their descendants, about 4 million people altogether, have the right to return to their original homes in Israel.

Israel rejects the demand as an attempt to undermine the Jewish character of their state, insisting that the solution to the refugee issue must come on the framework of a Palestinian state.