Israeli warplanes today struck Gaza, killing at least 12 Palestinians, including four children, a day after a rocket killed an Israeli man in the latest upsurge of violence.
Twenty-four Palestinians have been killed in the Gaza strip by Israel since yesterday, when a rocket attack on the border town of Sderot, an attack claimed by the Islamist Hamas group, killed an Israeli for the first time since May.
An Israeli helicopter attacked a police roadblock near the home of Hamas prime minister Ismail Haniyeh, wounding several people, Palestinian officials said.
The attack took place about 150 metres from Haniyeh's home in the Shati refugee camp in Gaza City. Haniyeh, who has been in hiding for several weeks, fearing Israeli assassination, was not believed to be in the area.
The Israeli army had no immediate comment. Most of the Palestinian dead were militants but also included six-month-old Mohammed al-Burai, who died in an air strike on the interior ministry.
Palestinian officials and medical workers said 10 civilians were among the dead. Four of them were boys, aged 10, 12, 13, 15, who were killed while playing football.
Christopher Gunness, a spokesman for the United Nations Relief and Works Agency, said the infant was the grandson of a guard living in a family home in the compound of an Unwra school struck in the attack by shrapnel and debris.
The boy's father carried his body, wrapped in a green Hamas flag, at a funeral attended by hundreds.
The latest wave of violence began yesterday when an Israeli air strike killed five Hamas militants in a van. Israeli officials said the dead included men who received weapons and explosives training in Iran. Local media reports quoted anonymous officials as saying the men were planning a large attack against Israel.
Hamas responded by firing more than 40 rockets into Israel, one of the heaviest barrages in months. One rocket landed in an Israeli college campus in Sderot, killing a 47-year-old father of four.
"We are at the height of the battle," the Israeli prime minister, Ehud Olmert, said in Tokyo, where he met the US secretary of state, Condoleezza Rice, before her visit next week to Israel and the occupied West Bank to try to push along peace talks.
But Olmert appeared to suggest a major Israeli ground operation in Gaza was not imminent, saying Israel's fight against militants was a "long process" and it had "no magic formula" to halt nearly daily cross-border rocket attacks.
Ismail Haniyeh, Hamas's top leader in Gaza, said in a statement: "Repeated crimes by the Zionist occupation against our people and the targeting of children are proof that the leaders of the occupation are suffering from hysteria."
Haniyeh and other Hamas leaders have been in hiding for several weeks, fearing assassination by Israel. Israeli planes yesterday attacked Haniyeh's office as well as the interior ministry.
Hamas seized control of Gaza last year from the Fatah forces of Palestinian President Mahmoud Abbas. Israel has been holding peace talks with the Abbas government in the West Bank, but there has been little progress since the US-sponsored peace conference in Annapolis, Maryland, last November.
Fatah condemned both the rocket attacks from Gaza and Israel's air strikes.
"These stupid missiles being launched - firecrackers, but at the end they have killed Israeli civilians - we condemn this, clearly, openly, straightforwardly," the Palestinian foreign minister Riyad al-Malki said.
"But at the same time, we condemn all the Israeli incursions into Gaza, killing Palestinian civilians, destroying their houses, preventing them from having a normal life."