Hamas leader Ismail Haniyeh said on Sunday that Israel's three-week offensive in the Gaza Strip was a failure and had not cowed the Palestinians, but praised his movement for deciding to declare a cease-fire.

"The enemy has failed to achieve its goals," Ismail Haniyeh, the top Hamas leader in the territory, said in a speech broadcast on Hamas television.

Though he called the war, in which more than 1,300 Gazans and 13 Israelis died, a "popular victory" for Palestinians, Haniyeh said Hamas's decision to declare a truce on Sunday was "wise and responsible".

Hamas announced an immediate cease-fire by its militants and allied groups in Gaza on Sunday, giving Israel a week to pull out its troops from the coastal territory.

Israel, which mounted an offensive against Hamas three weeks ago to halt years of rocket attacks, agreed to silence its guns and ground its aircraft early Sunday.

"We the Palestinian resistance factions declare a cease-fire from our side in Gaza and we confirm our stance that the enemy's troops must withdraw from Gaza within a week," said Damascus-based Hamas official Moussa Abu Marzouk.

Ayman Taha, a Hamas official in Cairo for talks with Egypt on a truce deal,
demanded that Israel open all of Gaza'sw border crossings to allow in food and other goods to meet the "basic needs for our people."

The cease-fire came after 22 days of fighting that killed some 1,200 Palestinians, about half of them civilians, according to Palestinian and United Nations officials. Ten Israeli soldiers and three Israeli civilians were killed during the campaign.

Israel said earlier on Sunday that it will not consider a timetable for withdrawing all of its forces from the Gaza Strip until Hamas and other militants cease their fire.

A leader of the militant Islamic Jihad in the Gaza Strip on Sunday said his group had also agreed to stop attacks on Israelis for a period of one week, following Israel's declaration of the unilateral cease-fire.

Daoud Shihab, the Islamic Jihad official, said other smaller militant groups have also agreed to join the truce. There has been no immediate response from Israel.

Shihab told The Associated Press that the factions will jointly make a formal announcement later on Sunday.

Shihab also said a longer cease-fire would be conditional on Israel withdrawing from Gaza the troops it sent into the Strip two weeks ago.

The Hamas announcement came after Gaza militants on Sunday fired at least 17 rockets into Israel, lightly wounding one man. One of Israel's stated goals in the campaign, code-named Operation Cast Lead, was the cessation of cross-border rocket fire.