Tel Aviv, Jan. 2 : Israel has killed a top Hamas commander and members of his family, prompting the Palestine-based militant outfit to redirect its rocket missiles on Israel''s main nuclear plant.

A London Times report said that forty-nine-year-old Nizar Rayan, his two wives and four children were killed on Thursday after Israel dropped a one-ton bomb on Rayan's home.

Rayan was among the Hamas'' top five decision-makers in the Gaza Strip.

His four-story apartment building crashed to the ground, sending a thick plume of smoke into the air and heavily damaging neighboring buildings. Apart from Rayan, 11 others, including two of his four wives and four of his 12 children were killed, Palestinian health officials said.

The Muslim faith allows men to have up to four wives.

Israel has made clear that no one in Hamas is immune in this offensive, and the strike that flattened Rayan''s apartment building in the northern town of Jebaliya drove that message home.

"We are trying to hit everybody who is a leader of the organization, and today we hit one of their leaders," Israeli Vice Premier Haim Ramon said in a television interview.

Though Hamas leaders went into hiding before Israel launched the offensive on Saturday, Rayan was known for openly defying Israel. Israeli military said he had an tunnel under his house that could serve as an escape route for Hamas terrorists.

Israeli military officials reportedly warned members of Rayan''s family not to stay in the home Thursday but they refused, saying they were human shields.

A professor of Islamic law, Rayan was closely tied to Hamas'' military wing and was respected in Gaza for donning combat fatigues and personally participating in clashes against Israeli forces. He sent one of his sons on an October 2001 suicide mission that killed two Israeli settlers in Gaza.

Israel launched the offensive to crush militants who have been terrorizing southern Israel with rocket fire from Gaza. It began after more than a week of intense Palestinian rocket fire that followed the expiration of a six-month truce.

Israeli warplanes have carried out some 500 sorties against Hamas targets, and helicopters have flown hundreds more combat missions, a senior Israeli military officer said Wednesday. More than 400 Gazans have been killed and some 1,700 have been wounded, Gaza health officials said. The U. N. says the death toll includes more than 60 civilians, 34 of them children. (ANI)