Isabel Kershner

Israel and Gaza were at war on Saturday after Palestinian militants launched an early morning assault on southern Israel that had few precedents in its complexity and scale, invading several Israeli towns and firing thousands of rockets toward cities as far away as Jerusalem.

The militants crossed into Israel by land, sea and air, according to the Israeli military. By late morning, at least 22 Israelis had been reported dead by the country’s main ambulance service, and Israel had retaliated with massive strikes on Gazan cities, killing at least one Palestinian, according to local reports.

Prime Minister Benjamin Netanyahu of Israel said operations were underway to clear the militants from infiltrated towns and that he had issued a call-up of reservists.

“We are at war,” he said in a televised statement.

The timing of the assault was striking, hitting Israel at one of the lowest moments in its history. It followed months of profound anxiety about the cohesion of Israeli society and the readiness of its military, a crisis set off by the government’s efforts to reduce the power of the judiciary. And the violence came 50 years and a day after the Yom Kippur War of 1973, when Israel was also surprised by a complex Arab attack, leading to huge Israeli losses and soul-searching about the state of the country.

Muhammad Deif, the leader of the military wing of Hamas, the Islamic militant organization that controls Gaza, said in a recorded message that the group had decided to launch an “operation” so that “the enemy will understand that the time of their rampaging without accountability has ended.”

Here is the latest:

  • The Israeli military said that at least 2,200 rockets had been fired into Israel by 11 a.m. on Saturday and that armed gunmen had crossed the border fence in several locations along Israel’s perimeter with Gaza, a poor coastal enclave that has been under blockade by Israel and neighboring Egypt for 16 years.

  • Palestinian militants infiltrated at least seven Israeli communities and army bases this morning, according to the Israeli military spokesman, Lt. Col. Richard Hecht. He said militants had reached the city of Sderot; the small towns of Kfar Azza, Nahal Oz, Magen, Beeri; the military bases of Reim and Zikim, which are close to towns of the same name; and the militarized border checkpoint at Erez. Fighting was ongoing at or near the at least three of those places, he said.

  • Al Qassam Brigades, the military wing of Hamas, said that there was a military operation “in defense of the Aqsa mosque,” the hotly contested holy site in Jerusalem that thousands of Jews have visited in recent weeks, and against the Israeli blockade.

  • Israeli hospitals said they had received hundreds of wounded. Soroka Medical Center in the southern city of Beersheba had admitted more than 80 people, with some “in very difficult condition,” a hospital spokeswoman said. The ambulance service, Magen David Adom, issued an urgent call for blood.