Two Palestinian suicide bomb attacks in 24 hours and the arrest of a Palestinian woman Israel said was preparing a suicide strike showed that Palestinians still have the will and the means to strike, Israeli officials said.

Meanwhile, Israeli Prime Minister Ariel Sharon faced an internal political crisis that might bring down his government. After two parties in his coalition failed to support a government economic measure in parliament on Monday, he fired the party's representatives, a move that could erase his parliamentary majority.

A Palestinian bomber blew himself up at a busy crossroads early Monday morning in northern Israel, killing only himself. The attack followed one on Sunday evening in which the bomber and three Israelis died.

Also Monday, Israeli troops entered the West Bank town of Tulkarem and arrested a woman who planned to carry out a suicide bombing, Israeli security sources said. Palestinian officials identified her as Thawriyeh Hamamreh, 24, from the village of Jaba near Jenin.

Israeli officials Monday also disclosed that a Palestinian plan to detonate a one-ton bomb in the parking lot beneath twin 50-story towers in Tel Aviv was thwarted three weeks ago. Troops raided a West Bank town, preventing the planned car bombing before it could be launched, according to an Israeli officer and an Israeli official.

The Israeli officer, who appeared before parliament's Foreign Affairs and Defense Committee, said Palestinian militants were attempting to rebuild their capacity to carry out bombing attacks. The officer and the government official, who was contacted by The Associated Press, both spoke on condition of anonymity.

A military sweep in the West Bank, launched March 29 amid the deadliest wave of suicide bombings ever faced by Israel, resulted in the killing or capture of hundreds of suspected militants and a sharp drop in the number of attacks.

Until Sunday, Palestinian militants had carried out only one suicide attack that killed Israelis in the past five weeks -- a May 7 bombing that killed 15 in a pool hall near Tel Aviv.

But Sunday a bomber disguised in an Israeli army uniform entered a produce market and set off his explosives, killing three Israelis and wounding dozens in Netanya, a coastal city that has been hit repeatedly by such attacks.

That was followed by a Monday morning bombing at the Taanakhim Junction, a few miles inside Israel, near the northern West Bank that killed only the bomber.

No group claimed responsibility for Monday's blast.

The Popular Front for the Liberation of Palestine, or PFLP, a radical PLO faction, said it carried out Sunday's attack and identified the bomber as 18-year-old Osama Boshkar from the West Bank's Askar refugee camp.

Boshkar's father, Adel, said he opposed the bombings.

"I'm against this kind of operation, which harms the Palestinian situation," he said.

PFLP leader Ahmed Saadat is detained in a Palestinian jail in the West Bank town of Jericho under British and U.S. supervision. Israel had demanded his detention, saying he is responsible for the killing of Israeli Tourism Minister Rehavam Zeevi last October.

The PFLP had claimed responsibility for killing Zeevi in an east Jerusalem hotel.

Deputy Defense Minister Dalia Rabin-Pelossof said there was no conclusive proof that Saadat ordered Sunday's bomb attack, but an Israeli government spokesman, Danny Shek, said Saadat "might have been instrumental in commanding and masterminding the bombing."

Saadat has given a phone interview from detention, and Israeli media reports said he has been visited by PFLP activists. British diplomats are seeking Israeli proof of the allegations against Saadat.

The prospect for renewal of peace talks, which broke down more than a year ago, appeared dim. Sharon says Palestinian violence must stop before contacts can be resumed and he says that he does not view Palestinian leader Yasser Arafat as a partner for negotiations.

The issue threatening Sharon's government from inside is economic. Objecting to parts of an emergency cutback program, two Orthodox Jewish parties did not vote for the plan in parliament, and it was defeated.

In response, Sharon fired the ministers and deputy ministers from the two parties, Shas and United Torah Judaism. The dismissals go into effect 48 hours after the letters were delivered early Tuesday, leaving time for last-minute deals.

If the parties leave the coalition, Sharon will be left teetering with the support of exactly half of the parliament.