Israel unleashed a massive new bombing campaign on Gaza City on Tuesday, September 16, after visiting United States Secretary of State Marco Rubio backed the ally's goal of eradicating Hamas and warned that only days may be left for a diplomatic solution.

Israeli Defense Minister Israel Katz said early Tuesday that Gaza City, the territory's main urban hub, was "on fire." He added: "The [Israel military] is striking with an iron fist at the terrorist infrastructure and [Israeli] soldiers are fighting heroically to create the conditions for the release of the hostages and the defeat of Hamas. We will not relent and we will not go back - until the completion of the mission."

Witnesses told Agence France-Presse (AFP) of heavy, relentless bombing on Gaza City, much of which is already in rubble after nearly two years of Israeli bombardment since the October 7, 2023 attacks by Hamas. The overnight strikes killed at least 12 Palestinians, including two children, according to Doctor Rami Mhanna, managing director of the Shifa Hospital in Gaza City, which received the bodies.

Another strike hit at least three houses on the southwestern side of the city, residents said. Medics were searching the rubble for survivors. "It was a heavy night," said Radwan Hayder, a Gaza City resident sheltering near the Shifa Hospital.

Mahmud Bassal, a spokesman for the Gaza civil defense agency, told AFP that as of early Tuesday, heavy bombing was ongoing in Gaza City "and the number of deaths and injuries continues to rise." Bassal said the Israeli military also targeted the southern city of Khan Yunis, after the civil defense agency reported Israeli strikes killed 49 people on Monday.

Rubio on Monday offered robust backing for the offensive as he met Israeli Prime Minister Benjamin Netanyahu, who has asked the Israeli military to seize Gaza City. In response, Netanyahu said Rubio's visit was a "clear message" that the US stood with Israel, and called US President Donald Trump "the greatest friend that Israel has ever had."

Pointing to the fresh operations, Rubio told reporters as he left Israel: "We think we have a very short window of time in which a deal can happen. We don't have months anymore, and we probably have days and maybe a few weeks to go."

Rubio said a diplomatic solution in which Hamas demilitarizes remained the US preference, although he added: "Sometimes when you're dealing with a group of savages like Hamas, that's not possible, but we hope it can happen."

Both Netanyahu and Rubio said on Monday the only way to end the conflict in Gaza is through the elimination of Hamas and the release of the remaining 48 hostages - around 20 of them believed to be alive - setting aside calls for an interim ceasefire in favor of an immediate end to the conflict. Hamas has said it will only free the remaining hostages in return for Palestinian prisoners, a lasting ceasefire and an Israeli withdrawal from Gaza.

Rubio's visit and the Israeli strikes come a week before France will lead a United Nations summit in which a number of Western countries, angered by what they see as Israeli intransigence, plan to recognize a Palestinian state.

Rubio called statehood recognition "largely symbolic," while Netanyahu - whose government is fervently opposed to such a move - said his country may take unspecified "unilateral steps" in response.

Members of Netanyahu's far-right cabinet have called for the annexation of the occupied West Bank, in order to prevent the establishment of a Palestinian state, triggering protests by the United Arab Emirates, which normalized ties with Israel five years ago.

Israel's defense minister says 'Gaza is burning' after heavy strikes overnight in Gaza City