Israel on Friday welcomed a temporary truce declared by Palestinian militants, and promised to hold its fire, but demanded that the Palestinian Authority eventually dismantle the armed groups.

Israel's vice prime minister, Ehud Olmert, said Israel will refrain from military offensives to help make the cease-fire a success. He told Army Radio that the declaration made in Cairo on Thursday was welcome, but did not go far enough.

He said Palestinian President Mahmoud Abbas was making an effort, adding every step that might lead to ending terrorism is a positive step.

The 13 main Palestinian groups announced they would halt attacks on Israel for the rest of the year, the longest-yet period of promised calm and a success for Mr. Abbas.  

A cease-fire will be useful for Israel. It will allow its withdrawal from the Gaza Strip and four West Bank settlements, without the threat of Palestinian fire. The controversial disengagement plan is expected to be a complicated operation, accompanied by strong resistance from Jewish settlers.

In June 2003, militant groups declared a unilateral three-month truce that collapsed after only six weeks. This time, however, analysts say the parties -- Israel, the Palestinian Authority, the militant factions, Egypt and even Syria and Iran -- have an interest in making the truce stick.

Israeli counter-terrorism analyst Boaz Ganor told Israel Radio that the militants' announcement is welcome.  But he said that, unless Abu Mazen, as Mr. Abbas is known, disarms the militants, no permanent end to hostilities should be expected, and that poses a serious threat to everyone.

"This can last weeks, this can last months, or this can last a year or two. But at the end of the day, neither Israel nor the United States, not even Abu Mazen himself, would agree to that [allowing militants to remain armed], because this is a real risk to his position as the head of the Palestinian Authority," said Mr. Ganor.

The declaration also comes as Hamas and, to a lesser extent Islamic Jihad, are making their first forays into Palestinian politics. For the first time, Hamas will field a slate of candidates in the parliamentary elections scheduled for July.

Last December and January, the militant group won strong support in local elections in the West Bank and Gaza. 

President Abbas hopes that, eventually, participation by Hamas and other militant groups in the political process can eventually lead to their disarming.