Gaza/Tel Aviv - Israel pressed on with its relentless air raids against Hamas on the seventh day of its Gaza offensive, striking some 20 targets of the radical Islamic movement ruling Gaza early Friday, a military spokeswoman said.

The military imposed a one-day closure on the West Bank which began at midnight and police were on high alert to prevent unrest during Friday's Muslim prayers at Jerusalem's al-Aqsa Mosque. Police limited entry to the Old City to Muslim men aged 50 or older from Israel or East Jerusalem, with Israeli identity cards.

Israel also announced that it would permit some 400 foreigners living in Gaza to leave the war zone on Friday, after receiving requests and coordinating with foreign embassies, Israel Radio reported.

More rocket launchers, rocket production workshops, a building storing "large amounts" of rockets, a tender carrying rockets and houses of Hamas activists were targeted, bringing the total number of targets hit in seven days of airstrikes to more than 700, the military spokeswoman said.

Hamas and other militant factions in Gaza also fired several hundred self-made and imported rockets at southern Israel. At least 350 "falls" were tracked down, but more may have been launched, the military said.

More than 50 rockets landed in Israel on Thursday, but none were fired overnight, she said.

The Palestinian death toll in the Israeli offensive has neared 420, after at least 21 Gazans died on Thursday, including 11 children and nine women - many of them from the family of the most senior Hamas leader killed by Israel in several years, Nizar Rayan, whose house in the northern Gaza Strip refugee camp of Jabaliya was all but demolished by Israeli rockets.

In defiance of Israel, Rayan, one of the more extremist members of Hamas, had refused to evacuate his home and go into hiding as most other Hamas leaders have. Hamas leader Ismail Radwan, speaking on Hamas television, vowed to avenge Rayan's death by hitting Israelis "everywhere."

More than 2,100 Palestinians have been wounded, and about 250 of them were in a critical condition on Friday. Four Israelis have also been killed by rockets and several dozen injured.

Jabaliya's Holfe Mosque was also destroyed in the overnight airstrikes, with Israel saying it was used as a "command centre" for Hamas militant activity.

The Israeli Air Force also bombed another arms smuggling tunnel under the border with Egypt. More than 100 such tunnels have been bombed since Sunday, the military spokeswoman said. (dpa)