Israel has continued air strikes on the Gaza Strip, hours after Palestinian militant group Hamas announced that it was ending rocket attacks on Israel.
Israel is threatening a sustained campaign against militants
Israel said it was targeting premises used to store or produce arms. No serious casualties were reported.
The Hamas announcement came after Palestinian militants in Gaza fired dozens of rockets into Israel.
Palestinian spokesman Saeb Erekat has called for international intervention to help stop escalating violence.
Mr Erekat told the BBC that he feared things were slipping out of control and third party intervention was needed.
He also urged a resumption of contacts between the Israelis and Palestinians.
Meanwhile Israeli leader Ariel Sharon faces a crucial leadership vote.
Members of the Likud party are due to decide whether to hold party leadership elections, in what is being seen as a referendum on Mr Sharon's premiership following the Gaza withdrawal.
Palestinian witnesses reported the attacks as follows:
- Helicopters fired two missiles into Gaza City, knocking out power in eastern districts
- Missiles slammed into Khan Younis in the south, damaging a building reportedly used by militants from the Popular Front for the Liberation of Palestine faction
- A missile landed in an open field near the southern border town of Rafah
- A missile hit an area near a road in the north of the strip used by militant rocket squads, the Israeli military said; one woman was said to have been injured by shrapnel.
Israeli Foreign Ministry spokesman Gideon Meir told the BBC it was now up to the Palestinian Authority to rein in the militants.
"What we expect now from the Palestinian Authority is to collect the illegal weapons," he said.
"They have 30,000 troops in Gaza and they are doing nothing in order to stop this kind of rocket shooting...," he said.
Up to 40 rockets were fired at Israel, weeks after its military withdrew from the territory.
Announcing the end to rocket attacks, the Hamas leader in Gaza, Mahmoud Zahar, said the organisation was committed to a ceasefire which militants declared earlier this year.
Zahar said Hamas wanted to protect the Palestinian people
Mr Zahar said that in stopping attacks on Israel, Hamas wanted to protect the Palestinian people from what he called Zionist oppression.
Palestinian leaders and Egyptian mediators had been pressing Hamas to stop.
The BBC's Alan Johnston says Hamas is in danger of being blamed by Palestinians for drawing Israel back into Gaza just two weeks after a withdrawal welcomed with huge relief by the local population.
On Sunday, an Israeli air strike killed two Islamic Jihad militants, including a commander, Mohammed Khalil.
They were the latest fatalities in a long weekend of violence, just a fortnight after Israeli troops withdrew from the Gaza Strip after 38 years.
Mr Sharon faces a leadership challenge, with the Likud central committee voting on Monday whether to back his rival and former prime minister, Binyamin Netanyahu.
Mr Netanyahu opposed Mr Sharon's decision to pull settlers out of Gaza, saying it would encourage Islamic militants to attack Israel.