GAZA CITY - At least nine people, including an 11-month baby, was killed and scores injured Wednesday, November 14, in a series of Israeli strikes in Gaza.
Israel had "declared the war and will pay a heavy price for that," Hamas spokesman Fawzi Barhoum told Aqsa TV.
Israeli jet fighters launched several air strikes in Gaza in a major military escalation against the Palestinian enclave.
Among those killed in the attacks was Ahmed Al-Jaabari, the head of Ezz El-Din Al-Qassam, the armed wing of the ruling Hamas group.
Hamas said Jaabari died along with an unnamed associate when their car was blown apart by an Israeli missile, Reuters reported.
Palestinians said nine people were killed, including a seven-year-old girl.
An 11-month baby of a staff in the British Broadcasting Corporation (BBC) office in Gaza was also killed in the Israeli attack.
Video from Gaza showed the charred and mangled wreckage of a car belching flames, as emergency crews picked up what appeared to be body parts.
The Israeli army said the attack on Jaabari was part of "an extensive program of direct offensive strikes against Hamas, Islamic Jihad" and other Palestinian groups.
Reuters witnesses reported numerous explosions around Gaza, with Hamas security compounds and police stations among the targets.
"This is an operation against terror targets of different organizations in Gaza," military spokesman Avital Leibovitch told reporters, adding that Jaabari had "a lot of blood on his hands".
Israel's intelligence agency Shin Bet said Jaabari was responsible for Hamas' takeover of the Gaza Strip in 2007 from rival Fatah of Western-backed president Mahmoud Abbas.
It said Jaabari instigated the attack that led to the capture of Israeli corporal Gilad Shalit in a kidnap raid from Gaza in 2006.
Jaabari was also the man who handed Shalit over to Israel in a prisoner exchange five years after his capture.
Chief Palestinian negotiator Saeb Erekat condemned the Israeli escalation in the Gaza Strip.
In an interview with CNN, Erakat labeled the attack the beginning of a "major, major Israeli escalation," and he called on the international community to pressure Israel to halt its operation.
The escalation came after days of Israeli attacks and Palestinian rocket fire into southern Israel.
It also came in a week when Israel pounded Syrian artillery positions it said had fired into the Israeli-annexed Golan Heights.
Israel hinted at a possible invasion of Gaza.
"There are preparations, and if we are required to, the option of a entry by ground is available, Brigadier-General Yoav Mordechai told Channel 2 TV.
In 2008, Israel killed more than 1,400 Palestinians and injured thousands in a three-week offensive in Gaza.The onslaught caused heavy destruction in the strip, home to 1.5 million Palestinians.