Palestinian militants have fired more than 400 rockets into Israel while Israel has pressed ahead with a series of deadly air strikes on the Gaza strip and Egypt has began efforts to mediate an end to the fighting.
The Israeli military said it hit more than 130 targets, including rocket-launching sites, as blasts sounded across the Palestinian enclave.
At least three people were killed in a late-night bombing of a building in the southern Gaza area of Khan Younis, medical officials said. The target appeared to have been a senior Islamic Jihad militant, a source in the armed group said, but the identities of those killed were not immediately confirmed.
In total, 24 Palestinians, including at least five women and five children, as well as three senior Islamic Jihad commanders and four gunmen have been killed since the fighting began, Palestinian health officials said.
Among the fatalities on Wednesday was a 10-year-old girl, although the circumstances of her death were unclear.
A collection of Islamic militant groups in Gaza unleashed a barrage of rockets into Israel, including dozens towards the major city of Tel Aviv.
Israeli officials said most were intercepted or fell in open areas, but Defence Minister Yoav Gallant said about one-quarter had been misfired and fallen inside Gaza. Israeli rescuers said three people were hurt running for shelter, and four homes in southern Israel were damaged by rocket strikes.
A state-run Egyptian TV station announced Egypt, a frequent mediator between the sides, had brokered a ceasefire. But the truce efforts appeared to falter as fighting intensified late on Wednesday, with neither side showing any sign of backing down.
Israeli Prime Minister Benjamin Netanyahu said in broadcast remarks that Islamic Jihad had sustained a serious blow, but cautioned: "The campaign is not over yet."
“We say to the terrorists and those who send them, 'We see you everywhere. You can't hide, and we choose the place and time to strike you,'” he said.
UN Secretary-General António Guterres condemned the civilian deaths in Gaza as "unacceptable" and appealed for the hostilities to "stop immediately" and for all parties to exercise maximum restraint, deputy UN spokesperson Farhan Haq said.
The 15-member UN Security Council met behind closed doors on Wednesday over the latest violence.
"Israel must abide by its obligations under international humanitarian law, including the proportional use of force and taking all feasible precautions to spare civilians and civilian objects in the conduct of military operations," Mr Haq said.
Mr Guterres also condemned the indiscriminate launching of rockets from Gaza into Israel, which violates international humanitarian law and puts at risk Palestinian and Israeli civilians, Mr Haq said.
"The secretary-general urges all parties concerned to exercise maximum restraint and to work to stop hostilities immediately," Mr Haq said in a statement.
Israel says the air strikes are a response to a barrage of rocket fire launched last week by Islamic Jihad in response to the death of one of its members from a hunger strike while in Israeli custody.
ABC/Reuters/AP