GAZA (AFP) -- Palestinian resistance fighters bombarded southern Israel on Thursday after a Hamas commander's house in northern Gaza was blown up in a blast which killed seven people, including a four-month-old baby.

The attacks started immediately after the explosion which Palestinian medics said also wounded 51 people, among them women and children, in and around the two-storey building.
The Israeli military said nearly 50 rockets and mortar rounds were fired from Gaza following the explosion, which Hamas blamed on the Jewish regime despite its denial of involvement.
“Israel decided to give a chance to the Egyptian initiative which could have brought calm to the south,” the Israeli prime minister's spokesman Mark Regev told AFP.
At meeting on Wednesday, the Israeli security cabinet also ordered the military to make the necessary preparations for a major ground offensive against Gaza if Egyptian-brokered truce talks fail to bear fruit.
A senior Israeli defense official was in Cairo on Thursday for a new round of the Egyptian-mediated negotiations.
Hamas laid out conditions for a truce with Israel, demanding “a lifting of the (Israeli) siege, with a precise timetable for opening the crossing points (out of Gaza) and a list of the categories of products that will enter the Gaza Strip.”
“It is important that the Rafah terminal (between Gaza and Egypt) be part of the project for calm,” said Hamas's Ismael Haniya.
The Israelis have been linking the opening of Rafah -- the only outlet for Gaza that does not pass through Israel -- to the freeing of Corporal Gilad Shalit, captured by Hamas and others two years ago.
Israel's opposition right-wing Likud leader Benjamin Netanyahu on Thursday called for a military offensive against Hamas in the Gaza Strip rather than any truce.
“The last thing to do is to allow Hamas to prepare for new attacks against Israel” through a truce, he told public television.
The Islamic resistance movement Hamas took power a year ago in the Gaza, an impoverished sliver of land, ousting forces loyal to Palestinian President Mahmud Abbas.
Witnesses said Thursday's blast that leveled a house in Beit Lahiya was caused by an Israeli air strike, but the Zionist army denied involvement, saying it could have been an accidental explosion.
The blast caused widespread devastation.
“The IDF (Israel army) has no connection whatsoever to the events the Palestinians are describing. Our air force and land forces did not operate at that time,” spokeswoman Major Avital Leibowitz told AFP.
Al-Aqsa television channel said the house belonged to a local commander of the armed wing of the Islamic resistance movement, and added that he was not at home at the time.
Many of the victims belonged to one family, said Muawiya Hassanein who heads the Gaza emergency services.
“We blame this crime on the Israeli occupation,” Hamas spokesman Taher Nunu said in Gaza City. “We are used to Israel not admitting to its crimes.”
Two Gaza resistance fighters were killed by Israeli forces earlier on Thursday in operations before the house blast and a clash after the explosion, Palestinian emergency services said.
At least 501 people, nearly all Palestinians and the majority of them Gaza resistance fighters, have been martyred since “peace” talks between Israel and the Palestinian leadership resumed last November, according to an AFP count.
That tally does not include the dead in Thursday's house blast.