A senior leader of the militant group Hamas has died after he was shot in an ambush by Israeli forces in Gaza, the Israeli army says.

Riyad Abu Zayd and his bodyguards came under fire from Israeli forces as they were driving in a car along the Gaza Strip's coastal road, reports said.

Zayd was wounded in the attack, and taken to a hospital in Israel, where he died of his wounds, according to a military spokesman.

The Israeli army said soldiers had wanted to arrest Zayd, considered to be an active military commander of Hamas.

Reports from Israel say troops shot Zayd when he pulled out a gun after his car was stopped.

Tanks enter

The attack came after the Israeli army launched a major overnight incursion into the Gaza Strip.

A Palestinian police officer and a civilian were said to have been shot dead in the raids which also left several others injured.

About 40 Israeli tanks and two bulldozers entered the area to the north of Gaza City and destroyed the home of a suspected Hamas member, Palestinian officials said.

Several Palestinian men who were inside the five-storey building were detained for questioning, according to witnesses.

Several other people were injured in machine gun fire from helicopters backing the mission, reports said.

Deadly blasts

Israel's military actions follow the death of four Israeli soldiers in the Gaza Strip on Saturday, killed when their tank was hit by a landmine placed by Hamas.

The raid also followed an unexplained blast which killed five Palestinians in southern Gaza City on Sunday.

Israeli troops demolished a number of Palestinian houses

Hamas representatives said the dead were Hamas activists. Several other people were injured in the explosion.

The Israeli army has refused to comment on the blast, fuelling speculation that it could have been part of its expected response following the tank attack on Saturday.

Accidents

However according to the Associated Press news agency, Hamas prevented journalists from inspecting the site.

Correspondents point out that Palestinian militants have accidentally blown themselves up while manufacturing bombs in the past.

Following the attack on the tank, Israeli Defence Minister Shaul Mofaz told a weekly cabinet meeting his troops would hit hard at Hamas in Gaza.

"Israel will land a serious blow against the Hamas infrastructure in the Gaza Strip," he said, quoted by the AFP news agency.