Ashkelon, Israel (CNN) -- Malka Davidovich's Sunday started as her days normally do. She went to work.
A nurse, Davidovich arrived at the Barzilai Medical Center in Ashkelon, Israel, where she was told her son, an Israeli soldier, was in the emergency room.
"The truth is, I didn't even know he was in Gaza," she said.
"So I ran to the emergency room and found him among a few other soldiers who were also wounded and had just arrived. To my joy, he was conscious, and he spoke to me, and my heart just kept going boom, boom, boom," said Davidovich.
Sunday was the deadliest day yet in the battle between Israel and Hamas militants in Gaza.
The Israel Defense Forces said 13 soldiers were killed.
Eighty-seven Palestinians died, at least 60 of them in Israel's assault on the town of Shaja'ia, the Gaza Health Ministry said.
"He kept asking about the fate of his friends, the other soldiers he was with. He didn't stop asking me. He gave me a list of the soldiers' names who he was with but some of them, I know, are not in good condition," said Davidovich, whose son suffered leg, eye and ear injuries.
Barzilai Medical Center is the closest Israeli hospital to the border. It treats civilians and soldiers. It also treats Palestinian patients brought in from Gaza, although none were there when CNN visited.
The hospital has been a frequent victim of rocket attacks. Sirens went off as Dr. Chezy Levy, the hospital's general manager, spoke.
To prepare for more casualties, the hospital has brought in more surgeons and cleared its operating schedule, he said. It has 12 surgical rooms, including five in reinforced shelters.
Levy said soldiers have been brought in with shrapnel wounds, gunshot wounds -- often to legs and arms -- and also other injuries consistent with a war zone.
"Since the campaign started with the infantry troops, we got a lot of casualties among the soldiers and we treated them here," he said.
In total, 425 Palestinians have been killed, according to the Gaza Health Ministry. It's unknown how many were militants. The United Nations has estimated that 70% were civilians.
Eighteen Israeli soldiers have been killed, in addition to two civilians. Israel has used its Iron Dome defense system to block many missiles, fired by militants in Gaza, from hitting population centers.