The Palestinians on Tuesday warned of "chaos and instability" after Israel's pullout from the Gaza Strip (search) and parts of the West Bank (search) if the Israelis don't show more flexibility on key security issues ahead of the withdrawal.

The comments came after an Israeli-Palestinian security meeting ended late Monday with no agreement on how to coordinate the Israeli withdrawal from the Gaza Strip and four West Bank settlements.

Palestinian Interior Minister Nasser Yousef (search) presented Israeli Defense Minister Shaul Mofaz (search) with a security plan in the meeting late Monday, but Mofaz was unimpressed, an Israeli Defense Ministry official said.

The Palestinians accused the Israelis of foot-dragging.

"Israel showed no flexibility and put obstacles before any opportunity of reaching understandings," the Palestinian Interior Ministry said in a statement. "The Palestinian side left the meeting with one conclusion: Israel is interested in having chaos and instability in the Gaza Strip."

The encounter took place just before Palestinian leader Mahmoud Abbas (search) left for Washington to meet with President Bush. Abbas said he will demand political and economic support from the United States and progress on the internationally backed "road map" peace plan.

Israeli Prime Minister Ariel Sharon (search), meanwhile, pledged cooperation with Abbas "so long as we do not risk our security," and demanded that Abbas quickly crack down on militants.

"We are willing to help Chairman Abbas as much as we can as long as we do not risk our security," Sharon said Tuesday during a visit to Washington. "That is the red line."

Sharon also promised to ask Israel's parliament to release 400 more Palestinian prisoners upon his return to Israel. Sharon's government has released 500 already. The fate of prisoners is a constant source of friction between Israelis and Palestinians.

The Israeli official, speaking on condition of anonymity, described Monday's security meeting as "difficult." Mofaz told Yousef that Israel would withdraw from the Gaza Strip this summer even if the Palestinians fail to coordinate the pullout.

"The disengagement will be implemented in any case but it must be ensured that it will not occur under fire," Mofaz's office said in a statement.

Palestinian officials counter that they have received little or no information about the pullout and have no way of planning for it.

Israel and the Palestinians fear that without proper preparations militants could open fire on Jewish settlers and soldiers during the evacuation or that looting and illegal land grabs will follow the withdrawal.

The Palestinian plan only details how security forces will prevent militant fire and looting, the defense official said. Mofaz demanded to know the exact number of troops that will be deployed and outline the training they will receive ahead of Israel's "disengagement," the official added.

Despite the bad feelings, the sides agreed to meet again next week.

Mofaz refused to agree to release prisoners and hand over three West Bank cities as Israel promised under a truce deal reached in February, said Tawfeeq Abu Khousa (search), spokesman for the Palestinian Interior Ministry. Mofaz also refused to allow the Palestinians to receive arms and other equipment the security forces need to improve their capabilities, saying no progress on those issues would be made unless militants are disarmed, Abu Khousa said.

Separately, Egyptian officials met Islamic Jihad officials in the Gaza Strip on Tuesday and were to meet later in the day with Hamas leaders in an attempt to prevent a shaky truce from collapsing.

A crisis between Hamas and Abbas' ruling Fatah faction (search) over the possible delay of parliamentary elections scheduled for July 17 threatens to destroy a cease-fire deal. Hamas has accused Fatah of working to delay the vote because it fears the militant group will strengthen politically after recent gains in municipal elections.

Abbas said he would consider postponing the vote — a day after the Palestinian Election Commission (search) said a delay would be necessary if parliament passes a new election law.

"We decided to hold an election on July 17, but if there are legal reasons that require it to be postponed we will consider that," Abbas told the Arab satellite network Al-Jazeera.

In another development, a gunbattle erupted between militants and police in the West Bank town of Jenin. One bystander was lightly wounded in the shooting that began when the militants refused to hand over the stolen car in which they were driving.