Israel ordered restraint Sunday after Palestinian militants fired a salvo of rockets at the Jewish state, violating a fledgling ceasefire less than two hours after it took effect in the Gaza Strip.
The rocket strike threatened the ceasefire agreement that came into effect at dawn and in which militants promised to halt rocket attacks in exchange for an Israeli withdrawal from the impoverished coastal territory.
The Israeli army completed its withdrawal from Gaza shortly after dawn, a military spokeswoman said.
The armed wings of the ruling Islamist Hamas movement and the radical Islamic Jihad, both of which signed on to the ceasefire accord, each claimed responsibility for the rocket attacks which hit the Israeli town of Sderot shortly before 8:00 am (0600 GMT), causing no casualties.
The attacks, which were condemned by both the Hamas-led government and Palestinian president Mahmud Abbas, marked an inauspicious start to the ceasefire which came into play at 6:00 am (0400 GMT).
But Israeli Prime Minister Ehud Olmert, vowing restraint and patience in the coming days, said he had ordered the army not to respond to the attacks.
"We will show restraint and patience in order to give the ceasefire a chance," said Olmert, speaking at the inauguration of a school in the Bedouin town of Rahat in southern Israel.
"I took into account the possibility that cease-fires do not materialise immediately to their fullest extent without any violations," he added. "There are violations of the ceasefire on the Palestinian side, but I instructed the security establishment not to respond."
Olmert said he was optimistic the ceasefire would soon be extended to include the West Bank.
Abbas condemned the rocket attacks and ordered Palestinian security forces to deploy across the northern Gaza Strip to prevent further violations of the ceasefire, according to senior Palestinian security officials in Gaza.
Palestinian prime minister and Hamas leader Ismail Haniya, meanwhile, insisted the ceasefire agreement stood and said the circumstances surrounding the morning's rocket strikes were being reviewed.
"There is a renewed commitment to the (ceasefire) agreement," Haniya told reporters in Gaza City after speaking with faction leaders. "We call on all to respect and help prevent any violations of this agreement which all the factions and forces have agreed to."
Despite his reassurances, however, Islamic Jihad renounced the ceasefire after Israel launched fresh operations in the West Bank overnight, a spokesman for the group's armed wing Suraya al-Quds told AFP.
"This morning there were incursions in (the northern West Bank city of) Jenin and also arrests," said Abu Ahmed. "We will not abide any ceasefire as long as the Zionist enemy does not totally adhere to it as well."
Under the ceasefire accord Palestinian militant groups were to stop firing rockets at Israel from dawn Sunday, with Israel in exchange promising to halt military operations and withdraw from the Palestinian territory.
The Palestinian Authority and Israel agreed to the ceasefire after a phone conversation between Olmert and Abbas, during which Abbas told the Israeli premier that the Palestinian factions were willing to stop firing rockets, according to Abbas spokesman Nabil Abu Rudeina.
In exchange, Israel promised to "respond favourably" and withdraw its forces which were mostly deployed in northern Gaza in a bid to combat the rocket fire, according to the army.
The United States welcomed the ceasefire agreement as a step toward peace.
"We welcome the announcement and see this as a positive step forward," said White House spokesman Alex Conant. "We hope that it leads to less violence for the Israeli and Palestinian people."
The five-month offensive in Gaza to counter Palestinian rocket attacks, which have become a near daily event since Israel withdrew from the Gaza Strip in 2005, has taken a hefty toll.
More than 400 Palestinians and three Israeli soldiers have been killed since the military launched a massive counter-offensive in late June aimed at rescuing a captured soldier and ending the constant rocket menace. But Israel has conceded it is helpless to stop the home-made projectiles from striking Israel. Although the rockets are inaccurate and rarely cause casualties, in the past two weeks they have killed two Israelis.