Israel killed the military commander of the Islamist group Hamas in a missile strike on the Gaza Strip on Wednesday and launched air raids across the enclave, pushing the two sides to the brink of a new war.

The attacks marked the biggest escalation between Israel and Gaza militants since a 2008-2009 conflict and came despite signs on Tuesday that neighboring Egypt had managed to broker a truce in the enclave after a five day surge of violence.

Hamas said Ahmed Al-Jaabari, who ran the organization's armed wing, Izz el-Deen Al-Qassam, died along with an unnamed associate when their car was blown apart by an Israeli missile. Palestinians said nine people were killed, including a seven-year-old girl.

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.

Israel confirmed it had carried out the attack on Jaabari and warned that more strikes would follow. 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".

Immediate calls for revenge were broadcast over Hamas radio.

"The occupation has opened the doors of hell," Hamas's armed wing said. Smaller groups also vowed to strike back.

"Israel has declared war on Gaza and they will bear the responsibility for the consequences," Islamic Jihad said.

The escalation in Gaza came in a week when Israel pounded Syrian artillery positions it said had fired into the Israeli-annexed Golan Heights amid a civil war in Syria that has brought renewed instability to neighboring Lebanon.

Hamas has been supported by both Syria and Iran, which Israel regards as a rising threat to its own existence due to its nuclear program.

Israel's intelligence agency Shin Bet said Jaabari was responsible for Hamas' takeover of the Gaza Strip in 2007, when the militant Islamist group ousted fighters of the Fatah movement of its great rival, the Western-backed Palestinian 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.

Israel holds a general election on January 22 and conservative Prime Minister Benjamin Netanyahu has come under pressure to respond firmly against Hamas, with residents of southern Israel complaining bitterly about repeated missile strikes

Hamas has been emboldened by the rise to power in neighboring Egypt of its spiritual mentors in the Muslim Brotherhood whom it views as a "safety net."

Some 1,400 Palestinians and 13 Israelis died in the 2008-2009 conflict. There was a lull in hostilities after that, but the violence has flared again in recent months and Israel has repeatedly warned of dire consequences unless Hamas and its fellow militants stopped rocket attacks.

In the latest confrontation, which appeared to have ended on Tuesday, more than 115 missiles were fired into southern Israel from Gaza and Israeli planes launched numerous strikes. Seven Palestinians, three of them gunmen, were killed. Eight Israeli civilians were hurt by rocket fire and four soldiers wounded by an anti-tank missile.

Helped by Iran and the flourishing contraband trade through tunnels from Egypt, Gaza militias have smuggled in better weapons since the war of 2008-09, including longer-range Grad rockets and anti-tank missiles of the type they fired last week at an IDF patrol vehicle.

But Gaza's estimated 35,000 Palestinian fighters are still no match for Israel's F-16 fighter-bombers, Apache helicopter gunships, Merkava tanks and other modern weapons systems in the hands of a conscript force of 175,000, with 450,000 in reserve.

Israel's shekel fell nearly one percent to a two-month low against the dollar on Wednesday after news of the Israeli airstrikes broke.