Israel and Gaza were on a war footing on Saturday after Palestinian militants launched one of the biggest attacks in years from the Gaza Strip, sending thousands of rockets into central and southern parts of the country as heavily armed gunmen crossed border fences into Israeli communities.

Within hours, Israeli fighter jets began airstrikes on targets inside Gaza, as Prime Minister Benjamin Netanyahu of Israel said on television: “We are at war.” Muhammad Deif, the head of the military wing of Hamas, the Islamic militant organization that controls Gaza, said earlier 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 are images from the confrontation.

Rockets being fired toward Israel from the Gaza Strip. The assault began without warning about 6:30 a.m. on the Jewish Sabbath, and almost 50 years to the day since a surprise attack by Egyptian and Syrian forces on Israel that set off the 1973 war.

Members of Israeli security forces carrying an injured person in Ashkelon, about 10 miles north of the Gaza Strip. A hospital there reported receiving dozens of people in the first hours of the assault, some in grave condition.

Palestinian militants riding a seized Israeli military vehicle. Militants infiltrated at least seven Israeli communities and army bases on Saturday morning, according to an Israeli military spokesman, Lt. Col. Richard Hecht.

An Israeli soldier in the southern city of Sderot, standing by the bodies of Israelis killed by Palestinian militants who entered from the Gaza Strip.

Smoke rising after Israeli strikes in Gaza. Dozens of Israeli fighter jets hit targets in the Gaza Strip, the Israeli military said.

Residents in the Gaza Strip fleeing from near the border with Israel.

Relatives mourning over the bodies of Palestinian militants at the mortuary of a hospital in Gaza City.

A building ablaze in Tel Aviv after rocket attacks.

Israeli rescue teams tending to a man in a building that received a direct hit in Ashkelon.

A damaged apartment in Ashkelon.

An Israeli military vehicle burning after it was hit by Palestinian gunmen.

Members of Israeli forces taking cover in Ashkelon.

People gathering at an area hit by rockets in Ashkelon.

Smoke rising in the Rehovot area, south of Tel Aviv, as rockets were launched from Gaza.

Palestinians breaking into the Israeli side of Israel-Gaza border fence.

Palestinians riding an Israeli military jeep in the streets of Gaza.

Looking out of a damaged building in Ashkelon.

Text by Victoria Kim