Israeli and Palestinian leaders have said they are committed to a ceasefire agreed for the Gaza Strip, despite Palestinian rockets landing in Israel.
Israel says it has pulled all its forces out of Gaza
Israeli Prime Minister Ehud Olmert has said Israel will show "patience and restraint", although the rockets were fired from Gaza after the truce began.
Mr Olmert said he hoped the ceasefire would also be applied to the West Bank.
Hamas leader Ismail Haniya said all Palestinian groups had made clear that they stood behind the ceasefire.
"Contacts were made with the political leaderships of the factions and there is a reaffirmation of the commitment of what has been agreed to," Reuters news agency quoted Mr Haniya as saying.
Palestinian Authority President Mahmoud Abbas has ordered his security forces to enforce the truce.
The move was welcomed by the US administration, which called it a "positive step forward".
Speaking on a visit to a school in southern Israel, Mr Olmert said Israel had "the strength to show the patience and restraint to allow the ceasefire to take hold.
"I have personally told our security forces to show restraint," he added
He said he hoped the agreement "can be extended into the West Bank and that it can lead to serious, direct negotiation which could lead to a full settlement".
Earlier, at least three rockets were fired into Israel, one of which landed in the town of Sderot, without causing harm.
Afterwards Mr Abbas ordered the Palestinian security forces to deploy in northern Gaza and enforce the ceasefire, Palestinian security sources said.
The BBC's Alan Johnston in Gaza says it is not clear whether this means that the security men will actually be expected to use force against militants who might be about to launch rockets.
They have been reluctant to do so in the past, he says.
Hamas' armed wing said it launched the attacks because some Israeli troops were still in Gaza, east of the town of Jabaliya, despite the Israelis saying they had pulled out all their troops overnight.
A statement from the smaller Islamic Jihad group, which also claimed responsibility, said it would not agree to a ceasefire while Israeli military activity continued in the occupied West Bank.
Our correspondent says it quickly became clear that leaders of the two groups were working to try to rein in their armed men.
Mr Abbas telephoned Mr Olmert on Saturday night to say he had agreement from all Palestinian factions that they would stop their rocket fire.
Mr Olmert's spokeswoman Miri Eisin told the BBC that the prime minister had agreed that Israeli forces would not initiate any offensive action after the ceasefire began.
Shortly after the truce came into effect, the Israeli army confirmed that all its troops had left Gaza.
Israel evacuated its settlements and military bases in Gaza last year after 38 years in the territory, but the military renewed ground operations after militants captured an Israeli soldier, Cpl Gilad Shalit, in a border raid in June.