By Nidal al-Mughrabi
GAZA (Reuters) - Palestinian Islamists vowed revenge against Israel on Friday for killing a senior Hamas leader and his family, and said all options including suicide bombs were now open to "strike at Zionist interests everywhere."
But Israel pressed on relentlessly with air strikes, one of which killed three Palestinian children aged between 8 and 12 years who were playing on a Gaza street, medics said.
The strike near the town of Khan Yunis was one of more than 30 carried out by on Friday, the seventh day of an offensive aimed at stopping Hamas rockets striking southern towns.
Islamist fighters fired rockets at Israel's port of Ashkelon in response, one of which blew out windows in an apartment building in the port of Ashkelon to the north of Gaza.
In Gaza City, a lucky few hundred foreign passport holders boarded buses in the pre-dawn murk to quit the Strip, with the help of the International Committee off the Red Cross, their governments and Israeli compliance.
"The situation is very bad. We are afraid for our children," said Ilona Hamdiya, a woman from Moldova married to a Palestinian. "We are very grateful to our embassy."
They left behind 1.5 million Palestinians unable to escape the conflict, a city waking up to another day of bombs, missiles, flickering electricity, queues for bread, tape-up windows and streets littered with broken glass and debris.
"We will not rest until we destroy the Zionist entity," said Hamas leader Fathi Hammad at the funeral of Nizar Rayyan, who was killed with four wives, eight children and four neighbours by an Israeli missile which hit his house on Thursday.
Spokesman Ismail Rudwan said that "following this crime, all options are now open including martyrdom operations to deter the aggression and to strike Zionist interests everywhere."
PROTESTS TURN VIOLENT
Bracing for protests and retaliatory violence, Israel sealed off the occupied West Bank to deny entry to most Palestinians and beefed up security at checkpoints.
There were street protests by Palestinians in major West Bank cities, not all of which were totally aimed at Israel. In Ramallah, supporters of Hamas clashed with supporters of Fatah, taunting the faction led by Western-backed Palestinian President Mahmoud Abbas as Israel's "collaborators."
Fist fights broke out and police fired in the air.
Elsewhere, protesters clashed with Israeli soldiers at checkpoints and some were reported wounded by Israeli gunfire.
A statement by Hamas spokesman Ismail Rudwan said Israel's "terrorism, massacre and holocaust will not break us and will not force us to raise a white flag ... killing begets killing and destruction begets destruction."
The death toll rose to 424 as some badly wounded succumbed to their injuries and a morning strike killed two Palestinians in a house Israel said concealed a tunnel and a weapons dump.
A quarter of the dead are civilians, the U.N. estimates, and some 2,000 Palestinians have been wounded. Gaza rockets have killed four Israelis in the south over the past week.
The bearded cleric Rayyan was the highest ranking Hamas official to be killed in the current offensive. He had called loudly for suicide bombings in Israeli cities.
Israel's armoured forces remained massed on the Gaza frontier in preparation for a possible ground invasion, despite international calls for a halt to the conflict. An Israeli naval vessel lying offshore fired at a greenhouse in southern Gaza.
Late on Thursday, Israeli war planes bombed the Jabalya mosque. Israeli security officials said it was a meeting place and command post for Hamas militants and the large number of secondary explosions after the strike indicated that rockets, missiles and other weapons had been stored there.
Nine mosques have had been hit since it began on Saturday.
"I will pray at home. You never know, they may bomb the mosque and destroy it on our heads," said one man buying humus from a street stand. Another was defiant: "What better than to die while kneeling before God?" he said.
(Writing by Douglas Hamilton; Editing by Jon Boyle)