A top Hamas commander was among seven people killed in more than 20 Israeli air strikes on the Gaza Strip, as Israel began an operation targeting armed groups.
Ahmad Jabari, the operational commander of Hamas's armed wing, the Ezzedine al-Qassam Brigades, was killed on Wednesday alongside his bodyguard, Mohammed al-Hams, in an initial Israeli strike on a car in Gaza City which took place just before 4:00 pm (14:00 GMT), the Islamist movement said.
Shortly afterwards, Israel pounded the Gaza Strip with another 20 air strikes, killing five more people, two of them children, Hamas health minister Mufid Mukhalalati said in a televised press conference at Gaza City's Shifa hospital.
He said another 30 people had been injured in the wave of strikes on targets across the territory which hit Gaza City, the northern town of Beit Lahiya and the southern city of Khan Yunis.
"The Israeli occupation has carried out more than 20 air strikes on targets and headquarters of the police and security in the Gaza Strip," interior ministry spokesman Islam Shahwan said.
The attacks on Wednesday marked the biggest escalation between Israel and Gaza fighters since the 2008-2009 conflict and came despite signs on Tuesday that neighbouring Egypt had managed to broker a truce in the territory after a five-day surge of violence.
Israel's Shin Bet domestic intelligence agency and the military also confirmed the operation.
"During a joint operation of the General Security Service [Shin Bet] and the IDF [army] today, Ahmed Jabari, the senior commander of the military wing of Hamas in the Gaza Strip, was targeted," a statement from the Shin Bet said.
The military said Jabari "was a senior Hamas operative... directly responsible for executing terror attacks against the State of Israel in the past number of years".
"The purpose of this operation was to severely impair the command and control chain of the Hamas leadership, as well as its terrorist infrastructure," it said in a statement.
'Start of operation'
Israel sent a "clear message" to Hamas through the killing of its top military commander and is ready to "expand" its operation in Gaza if necessary, Israeli Prime Minister Benjamin Netanyahu said.
"Today we sent a clear message to to Hamas and other terrorist organisations, and if it becomes necessary we are prepared to expand the operation," he said in a televised address.
Military spokeswoman Avital Leibovich said the strike was the start of an operation targeting armed groups in Gaza following multiple rocket attacks on southern Israel.
"The IDF started an operation against terror organisations in Gaza due to the ongoing attacks against Israeli civilians," she said on her Twitter account.
Leibovich confirmed to Al Jazeera that Jabari was targeted specifically.
"The first target we targeted was Ahmad Jabari. A short time ago we completed another phase in the operation which included 20 different targets of rocket launcher pads," she said.
"Israel is exercising its right to protect itself, and Jabari has a lot of Israeli blood on his hands."
She went on to say that "there are 1.5 million people in Gaza, and even though we were targeted on a daily basis, we still helped Gazans in our hospitals because we are humanitarian people."
Asked whether Israel was ready to initiate a ground operation in Gaza, Leibovich said: "All options are on the table for us. We will do whatever necessary to protect the people of Israel."
Responding to the killing, the Ezzedine al-Qassam Brigades said its fighters would "continue the path of resistance".
"The occupation has opened the gates of hell on itself," it said in a statement.
Al Jazeera's Nadim Baba, reporting from Gaza, said Israeli strikes were still going on into Wednesday evening.
"We have been hearing of strikes in different areas of the Gaza Strip," he said. "For the civilian population here it is a very worrying time. People have deserted the streets, and it is very quiet and very tense."
He added that eye witnesses have reported seeing the Israeli navy off the coast of Gaza, further increasing their concerns.
Calls for revenge
Jabari headed of the Ezzedine al-Qassam Brigades. He co-ordinated much of Hamas's military capability, its military strategy, and the transformation of the military wing.
He also led the final negotiations in Cairo that concluded the prisoner swap between Hamas and Israel in 2011.
The killing of Jabari sparked furious protests in Gaza City, with hundreds of members of Hamas and the Ezzedine al-Qassam Brigades chanting for revenge inside Shifa hospital.
Outside, armed men fired weapons into the air, and mosques throughout the city called prayers to mourn the commander's death.
Osama Hamdan, a Hamas representative in based in Lebanon, talking to Al Jazeera in Doha, confirmed that Jabari's son was also killed in the targeted air strike that killed the military chief.
"We will respond [to the assassination], this I have to say clearly."
"The Israelis are working to target the local leaders and political leaders in Gaza. We are expecting acts and reactions from the Palestinians."
Saeb Erekat, a Palestinian negotiator based in the West Bank, told Al Jazeera: "We condemn this Israeli crime and assassination of Ahmad Jabari.
"We are witnessing a major escalation against our people in Gaza, and it seems to me the Israeli agenda is war, not truce or a ceasefire. We hold the Israeli government responsible."
Palestinian security sources and medics confirmed a total of four air strikes across Gaza during the late afternoon, two in Gaza City, one of which killed Jabari, one in northern Gaza, and a fourth in the southern city of Khan Yunis.
Wednesday's attacks come after several days worth of Israeli air strikes on the Gaza Strip, leaving at least seven Palestinians dead and several more wounded.
Al Jazeera’s Rula Amin, reporting from Beirut, Lebanon, said Jabari had been a target for Israel for a long time.
"This is a big loss for Hamas, and a success for Israel, who have been after him for a while." she said.
“We will see an escalation for sure within the immediate future.”
“People in Gaza know him. He was considered very smart, very shrewd, considered to be a hero because he had managed until now to escape numerous assassination attempts by Israel.”
“People will be bracing for more violence, not just against Hamas but against the civilians too.”