Six people, including women and children, have been killed in an Israeli air raid on the house of a Hamas member, as Israeli tanks and troops pushed into the central Gaza Strip.

Israel has pledged to continue the operation, which has already cost the lives of more than 60 Palestinians, until the abducted soldier is freed and crude rocket attacks over the border are stopped.

Dozens of armoured vehicles moved into central Gaza overnight on Wednesday, cutting the main road down the territory from which Israel withdrew less than a year ago after a 38-year occupation.

Israel has rejected calls from the governing Hamas movement for negotiations on a prisoner swap. Hamas accuses Israel of using the offensive to try to topple its elected government.

In an attempt to kill senior commanders of Hamas's armed wing, an Israeli air raid brought down a three-storey building on the northern edge of Gaza City.

At least six people, including two women and two children, were killed in the attack that turned the house into a tangle of twisted metal, broken concrete, blood and dust.

Israel said the man who has topped its wanted list for a decade was wounded.

But the military said it did not know how badly top fugitive Muhammad Daif, a Hamas who escaped previous assassination attempts, was hurt.

Palestinian medics confirmed that Daif had been wounded and operated on. Another 23 people were also wounded in the attack.

Hamas denial

Abu Obaida, the spokesman for Hamas's military wing, squarely denied the report.

"We categorically deny that Daif was wounded... This deceitful information intended to cover up Zionist crimes," he told reporters.

He also said the attack would "change all standards, opening new options that never have been used."

Chemical and radioactive weapons

Palestinians medics and officials accused Israel, meanwhile, of using new weapons in its latest offensive, speculating that they might be chemical or radioactive.

Bassem Naim, the health minister, said the weapons were causing severe wounds which physicians were unable to treat while dead bodies reaching hospitals in Gaza were charred and mutilated.

In Gaza City's Shifa hospital, Dr al-Saqqa supported the claims.

"Even bodies of the injured have been almost completely burnt. They have been deformed in a very ugly way that we have never seen before," he told Aljazeera channel.

Al-Saqaa, who heads the hospital's emergency service, said relatives had been unable to identify the dead victims.

"When we try to X-ray dead bodies, we find no trace of the shrapnel that hit the person killed," he said, adding that the bodies seemed to have been chemically burnt.

"We are sure that Israel is using a new chemical or radioactive weapon in the new operation. More than 25% of the injured are children, aged under 16."

Qatar moots new UN Gaza resolution

Qatar has circulated a revised draft of a United Nations Security Council resolution demanding Israel's immediate withdrawal from Gaza as well as the release of a captured Israeli soldier held by Palestinian resistance groups.

The latest version of the draft, first proposed in the 15-nation council last Thursday, added several provisions in an attempt to win broader support, after some members criticised the text as biased against Israel.

However, John Bolton, the US ambassador to the UN, said it remained flawed and that Washington still saw no need for council action.

The initial draft, put forward by Qatar, the council's sole Arab member, on behalf of Arab, Islamic and non-aligned states at the UN, condemned Israel's arrest and detention of dozens of elected Palestinian officials.

The new draft added language expressing "grave concern" about the firing of rockets from Gaza into Israel and condemning "all acts of violence, terror and destruction", including the recent abduction and killing of an Israeli civilian in the West Bank.

It called on the Palestinian Authority to "take immediate and sustained action to bring an end to violence, including the firing of rockets on Israeli territory" and for emergency aid to be provided for the Palestinian people.

Junior council diplomats met on Tuesday afternoon to revise the text and suggest further changes.

However, Bolton told reporters that US still considered the draft resolution as "unsatisfactory".

PHOTO CAPTION

An injured Palestinian child cries at a hospital in Gaza City. (AFP)