Israel stepped up its attacks on the Hamas-ruled Gaza Strip on Tuesday, drawing a heavy barrage on the country’s commercial heartland as the latest outbreak of violence edged closer to all-out war. “Hamas will receive blows here that it did not expect,” Prime Minister Benjamin Netanyahu said after the first fatalities on the Israeli side since fighting escalated a day earlier. The bombing of an empty high-rise building in Gaza hours later drew the waves of rocket fire on metropolitan Tel Aviv. The prime minister warned that Palestinian militants would pay a “very heavy price for their aggression.” In all, more than two dozen militants and civilians have died in Gaza and three civilians in Israel. The escalation has set off a flurry of diplomatic efforts to defuse the violence involving Egypt, the U.S. and United Nations. U.S. President Joe Biden directed his team to engage Israeli and Palestinian officials in an attempt to de-escalate tensions and met with his national security adviser on Tuesday to discuss the escalating violence. Rocket squads began firing hundreds of salvos at southern Israel on Monday evening, in a sharply intensified spillover from weeks of clashes between Israeli security forces and Palestinians in contested Jerusalem. The holy city, home to Jewish, Muslim and Christian shrines, lies at the heart of the Israeli-Palestinian conflict, and competing claims to it have underpinned the latest confrontation. Israeli aircraft have launched hundreds of raids on militant facilities, including infiltration tunnels and rocket production sites, and assassinated several military commanders since the bombardment began. On Tuesday evening, a 13-floor residential building was bombed after residents were warned to evacuate, a pressure tactic the Israeli military has used in the past, along with assassinations, to try to force Hamas to cease fire. Militants retaliated with more than 100 rockets on metropolitan Tel Aviv, and a new barrage on the south. A woman in a Tel Aviv suburb was killed, and three others were wounded elsewhere following a direct hit on a bus, Channel 13 TV reported. Flight arrivals and departures at Ben-Gurion International Airport were suspended during the rocket fire, a routine procedure, according to Ofer Lefler, a spokesman for the aviation authority. “The occupation set this fire in Jerusalem and is responsible for any bombing that takes place,” Hamas leader Ismail Haniyeh said. “If the occupation wants to escalate, then the resistance is ready, and if it wants to stop, the resistance is also ready.” The Israeli military warned Gaza residents on Twitter that it was striking Hamas weapons stores hidden inside civilian buildings and urged them to stay away from such sites. Other high-rises were hit after being warned to evacuate. The Israeli government called up 3,000 reserve soldiers as it prepared for the heightened offensive. Military spokesman Lieutenant-Colonel Jonathan Conricus said troops were being sent to the border with the Palestinian coastal enclave in case militants tried to attack through underground tunnels. They weren’t being dispatched for a ground invasion, but “for those of you hoping for a quick return to normal activity, that does not seem to be the case,” Conricus told reporters in a phone briefing. Israel and Gaza have skirmished repeatedly since Hamas took control of Gaza in 2007, and have fought three wars, the last seven years ago. Egypt, which historically has been involved in efforts to defuse violence between the sides, said it has been contacting regional and international actors this time, too. UN Secretary-General Antonio Guterres said the organization was “working with all relevant parties to de-escalate the situation urgently.” The U.S. held up a statement at the UN Security Council this week that would have expressed concern about the clashes, according to diplomats familiar with discussions. The Security Council will meet in a closed session on Wednesday morning to continue discussions, diplomats added. Subscribe to our YouTube channel: https://bit.ly/2TwO8Gm Bloomberg Quicktake brings you live global news and original shows spanning business, technology, politics and culture. Make sense of the stories changing your business and your world. To watch complete coverage on Bloomberg Quicktake 24/7, visit http://www.bloomberg.com/qt/live, or watch on Apple TV, Roku, Samsung Smart TV, Fire TV and Android TV on the Bloomberg app. Have a story to tell? Fill out this survey for a chance to have it featured on Bloomberg Quicktake: https://cor.us/surveys/27AF30 Connect with us on… YouTube: https://www.youtube.com/user/Bloomberg Breaking News on YouTube: https://www.youtube.com/c/BloombergQuickTakeNews Twitter: https://twitter.com/quicktake Facebook: https://www.facebook.com/quicktake Instagram: https://www.instagram.com/quicktake