GAZA CITY, Gaza Strip (AP) -- Israel launched dozens of airstrikes early Saturday in the southern Gaza Strip as part of a large-scale search for a soldier Israel suspects was captured by Hamas fighters.
At least 35 Palestinians were killed in the bombardment and shelling in and around the city of Rafah early Saturday, a Palestinian health official said, adding that the area's main hospital was evacuated because of the strikes.
The Israeli military has said it believes the soldier was grabbed in a Hamas ambush about an hour after an internationally brokered cease-fire took effect Friday morning.
The Hamas military wing on Saturday distanced itself from the soldier's purported capture, which has prompted widespread international condemnation. President Barack Obama and U.N. chief Ban Ki-moon have called for his immediate release.
The Hamas military wing later said in a statement on its website that it is "not aware until this moment of a missing soldier or his whereabouts or the circumstances of his disappearance."
The group said it believes the soldier might have been killed in a clash with Hamas fighters about an hour before the start of the cease-fire.
Hamas said it has lost contact with those fighters and that "we believe all members of this group have died in an (Israeli) strike, including the Zionist soldier the enemy says disappeared."
The Israeli military declined comment on the statement.
The disappearance of the soldier, 2nd Lt. Hadar Goldin, and the heavy clashes that followed it shattered an internationally brokered cease-fire that was to have been in place for three days and open the way for talks in Cairo on a more sustainable truce.
Israel and Hamas have accused each other of violating the humanitarian pause.
The breakdown meant there would be no reprieve for the 1.7 million residents of Gaza, where large parts have been devastated by airstrikes and shelling. More than 1,650 Palestinians -- mostly civilians -- have been killed and more than 8,000 wounded, according to health official Ashraf al-Kidra.
Israel has lost 63 soldiers and three civilians.
The fighting in Rafah intensified after the disappearance of the soldier and continued Saturday morning, with residents reporting airstrikes along the Egypt-Gaza frontier as well as heavy tank and artillery shelling. The Israeli military said it was searching for the missing soldier and had sent automated calls or text messages to Rafah residents to stay indoors.
"We are under fire, every minute or so tanks fire shells at us," said Rafah resident Ayman Al-Arja. "I have been thinking of leaving since 2 p.m., but tank fire can reach anywhere, and I was scared they will hit my pickup truck. Now we are sitting in the stairwell, 11 members of my family, my brother, his nine children and wife. We just have water to drink and the radio to hear the news."
The 45-year-old Al-Arja added: "We are just staying put waiting for God's mercy."
Since Friday morning, more than 100 Palestinians have been killed in the Rafah area, including 35 early Saturday, al-Kidra said.
The police operations room reported 77 airstrikes on the area and heavy shelling.
The Israeli military said Goldin disappeared in an ambush about an hour after the cease-fire began. Gunmen emerged from one or more Gaza tunnels and opened fire at Israeli soldiers, with at least one of the militants detonating an explosives vest, said Israeli army spokesman Lt. Col. Peter Lerner.
Goldin, a 23-year-old from the central Israeli town of Kfar Saba, was apparently captured in the ensuing mayhem, while another two Israeli soldiers were killed. "We suspect that he has been kidnapped," Lerner said.
Obama called for Goldin's unconditional and immediate release and said it would be difficult to put the cease-fire back together. However, he said the U.S. will continue working toward a cease-fire.
He said Israel committed to the truce, but at the same time called the situation in Gaza "heartbreaking" and repeated calls for Israel to do more to prevent Palestinian civilian casualties.
"Innocent civilians caught in the crossfire have to weigh on our conscience, and we have to do more," Obama said. He added that Israel must be able to defend itself, but that irresponsible actions by Hamas have put civilians in danger.
Israel has gone to great lengths in the past to get back its captured soldiers. In 2011, it traded hundreds of Palestinian prisoners for an Israeli soldier who had been captured by Hamas-allied militants in 2006. The capture of two soldiers in a cross-border operation by Lebanon's Hezbollah guerrillas in 2006 sparked a 34-day war between the Iranian-backed Shiite group and Israel.