Israel is on heightened security alert today after Hamas declared a "day of wrath" after the killing of a senior Hamas leader in Gaza.

Thousands of security personnel were on alert after the Islamists called for "massive marches" after the main weekly Muslim prayers, starting off from the Al-Aqsa mosque compound in Jerusalem and from all other mosques in the West Bank.

Witnesses said that violent scenes had been reported in east Jerusalem, with protesters throwing rocks at soldiers. Police spokesman Micky Rosenfeld said that thousands of extra officers had been deployed to deal with the ongoing clashes.

The Israeli Army also locked down the West Bank for 48 hours, with movement in and out of the territory prohibited except for emergencies and special cases.

Hamas made its latest threats after an air strike killed Nizar Rayyan and several of his wives and children. At least 422 Palestinians have now been killed in Israel’s seven-day offensive, of whom Mr Rayyan is the most prominent Hamas member.

It is the most high-profile targeted killing carried out by Israel since Abdel Aziz al-Rantissi in 2004, and Hamas again warned that it would resume suicide operations against Israel for the first time since January 2005.

"After the last crime, all options are open to counter this aggression, including martyr operations against Zionist targets everywhere," Hamas official Ismail Radwan vowed after the attack.

As Israel prepared for riots — and with massed tanks and troops ready for a threatened ground offensive around Gaza — the Israeli Army allowed foreigners to leave the battered enclave.

"The [border] crossing was specially reopened to allow foreign nationals to leave the Gaza Strip," an army spokesman said, adding that more than 400 people, mostly those with dual nationality, were expected to cross.

As Hamas's rocket fire continued to hit Israel's southern towns, the country's military pounded the densely populated Strip in the seventh day of an operation Israel calls Operation Cast Lead. It carried out around 20 strikes overnight, bombing rocket-launching sites and Hamas buildings, the Army said.

Among the targets hit by Israel was a mosque in the northern town of Jabaliya that the military said was a "terror hub" used to stockpile weapons and as a Hamas operations centre. At least two people were killed in the Jabaliya raids, medics said.

Despite Israel's military action, Hamas showed no sign of stopping the rocket fire which the Jewish State said that it had instigated its offensive. Gaza militants have fired more than 360 rockets into Israel, killing four people and wounding dozens more. Some of the rockets have reached deeper than ever before inside Israeli territory, penetrating around 24 miles from the Gaza border.

The Times today reported that Israeli officials fear that Hamas has purchased dozens of Iranian-made Fajr-3 missiles with an even longer range, capable of hitting its secret nuclear installation at Dimona, 20 miles east of Beersheba, the desert capital that has itself come under attack.

The Israeli offensive — one of its deadliest on Gaza — continued to spark angry protests in the Muslim world and defied diplomatic efforts to broker a truce. In the latest protests more than 4,000 Muslims demonstrated in Sydney and hundreds of Muslims burnt Israeli flags in Indian-administered Kashmir.

Tzipi Livni, the Foreign Minister, reiterated that Israel would not declare a truce after talks in Paris yesterday with President Nicolas Sarkozy and other French leaders. "The question of whether it’s enough or not will be the result of our assessment on a daily basis," she said.

Peace moves were also stalled at the UN Security Council even though UN Secretary General Ban Ki-moon said that the conflict had become "a dramatic crisis".

The civilian population in Gaza and stability throughout the Middle East were trapped, he said, "between the irresponsibility displayed in the indiscriminate rocket attacks by Hamas militants and the disproportionality of the continuing Israeli military operation".

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