JERUSALEM — Israeli aircraft bombed targets across the Gaza Strip and Gaza militants fired rockets into Israel early Tuesday, the second day of cross-border fighting that erupted in the last stretch of a closely contested race for Israeli prime minister between the long-serving incumbent and an ex-army chief.
The latest violence was triggered by a surprise rocket fired early Monday from Gaza, a territory ruled since 2007 by the Islamic militant group Hamas. The rocket slammed into a house in central Israel and injured seven people.
In response, Israeli Prime Minister Benjamin Netanyahu said he would cut short a visit to Washington, Israel sent troop reinforcements to the Gaza border and Hamas leaders went into hiding — signals that both sides are heading into perhaps the most serious confrontation since a 2014 Israel-Hamas war.
Late Monday, Hamas announced a cease-fire had been brokered by Egyptian mediators, but the cross-border strikes continued into early Tuesday.
The conflagration comes at a time when both Netanyahu and his Hamas foes are in desperate situations, with little incentive to de-escalate quickly.
Netanyahu is in a tight race for re-election against former army chief Benny Gantz. Just two weeks before the April 9 vote, he faces tough criticism from political rivals, including in his own right-wing political camp, who accuse him of being too soft on Hamas.
Hamas, meanwhile, is under growing pressure domestically because of its failure to get Israel and Egypt to ease their Gaza border blockade, imposed after the 2007 Hamas takeover.
Netanyahu signaled a tough response.
"Israel will not tolerate this. I will not tolerate this," he declared during a White House meeting with President Donald Trump.
"Israel is responding forcefully to this wanton aggression," he said. "We will do whatever we must do to defend our people and defend our state."
Israel opened public bomb shelters in most major cities and civil defense authorities canceled sports events and public transportation in southern Israel.
The Israeli army said several dozen rockets had been fired into Israel on Monday and Tuesday, as air raid sirens wailed across southern Israel. The army said nearly all rockets were either intercepted or landed in open areas.
Israeli airstrikes hit military sites for Hamas and the smaller Islamic Jihad group. Gaza's Health Ministry said seven Palestinians were injured in the airstrikes.
Targets included the office of Hamas leader Ismail Haniyeh. The Israeli military confirmed the bombing, saying the building had "served as an office for many military meetings."
Haniyeh issued a statement warning Israel against heavy retaliation. He said the Palestinian people "will not surrender" and its militant factions "will deter the enemy if it exceeds the red lines."
Another blast destroyed a multistory building in Gaza City that Israel said had served as a Hamas military intelligence headquarters. The airstrike was so powerful it sent debris flying onto the roof of The Associated Press bureau on the 11th floor of a nearby high-rise.
In Beirut, the powerful Lebanese militant group Hezbollah said its leader, Hassan Nasrallah, met Monday with a senior Hamas delegation. Hezbollah said they discussed the Gaza situation and "Israeli aggression."
Hamas is facing perhaps its toughest domestic test since seizing control of Gaza from the rival Palestinian Authority 12 years ago.
An Israel-Egyptian blockade, imposed to weaken Hamas, combined with sanctions by the Palestinian Authority and mismanagement by the Hamas government, have all fueled an economic crisis that has left Gaza with an unemployment rate above 50 percent.
Hamas has been leading weekly protests along the Israeli border for the past year in hopes of easing the blockade, but the demonstrations, in which some 190 people have been killed by Israeli fire, have done little to improve conditions.
Last week, hundreds of Gazans protested the dire conditions, a rare expression of public discontent against the authoritarian government. Hamas responded with a violent crackdown, beating and arresting dozens of demonstrators and drawing rare public criticism.
The rocket attack, which caught Israel off guard, may have been an attempt by Hamas to divert attention from its growing domestic woes.
Israel and Hamas have fought three wars. Although neither side appears to have an interest in another war, fighting could easily spin out of control. The 2014 conflict lasted 50 days and ended with over 2,000 Palestinian deaths, including hundreds of civilians, and 73 killed on the Israeli side.
Netanyahu faces the difficult task of delivering a tough blow to Hamas while avoiding protracted fighting that could work against him on election day.
Monday's attack came 10 days after rockets were fired from Gaza toward Israel's densely populated commercial capital of Tel Aviv, and the Israeli military struck back. Gaza's Hamas leaders said the rocket was fired accidentally and the fighting quickly subsided.