Photo: The Canadian Press. All rights reserved.

A man stands in front of a van damaged from a rocket fired from Gaza which landed in the middle of a residential neighborhood in the southern city of Kiryat Gat, Israel, Thursday, July 31, 2014. (AP Photo/Tsafrir Abayov)

Israeli forces, backed by heavy tank fire and airstrikes, moved deeper into southern Gaza late Friday in search of a soldier apparently captured in a clash with Hamas militants earlier in the day. At least 62 Palestinians and two Israeli soldiers were killed in the fierce fighting that quickly shattered a U.S.-brokered cease-fire.

The truce collapsed less than two hours after it began. The Israeli Cabinet held a rare session after the start of the Jewish Sabbath on Friday evening to weigh options, including whether to expand the 25-day-old operation against Hamas.

In Gaza's southern Rafah area, the military urged residents in phone calls to stay indoors as troops advanced.

"We are under fire. Every minute or so, tanks fire shells," said Ayman al-Arja, 45, a resident of the area.

Meanwhile, U.N. Secretary-General Ban Ki-moon blamed Hamas for violating what was meant to be a three-day humanitarian cease-fire and demanded the immediate and unconditional release of the missing soldier.

Both Israel and Hamas accused each other of breaking the cease-fire, which had been announced by the U.S. and the U.N. and took effect at 8:00 a.m. Friday.

The breakdown of the truce and the apparent capture of the Israeli soldier set the stage for a major escalation. The conflict has already devastated large swaths of the coastal area and killed at least 1,500 Palestinians, mainly civilians, according to Palestinian officials. Israel has lost 63 soldiers and three civilians.

An hour after Friday's cease-fire started, gunmen emerged from one or more Gaza tunnels and opened fire at Israeli soldier, with at least one of the militants detonating an explosives vest, said Israeli army spokesman Lt. Col. Peter Lerner.

Hadar Goldin, a 23-year-old 2nd Lt. from the central Israeli town of Kfar Saba, was apparently captured during the ensuing mayhem and taken back into Gaza through a tunnel, while another two soldiers were killed.

"We suspect that he has been kidnapped," Lerner said.

The White House condemned the incident, describing it as an "absolutely outrageous" action by Hamas. Deputy National Security Adviser Josh Earnest said the soldier must be released immediately.

Israeli Prime Minister Benjamin Netanyahu, meanwhile, told U.S. Secretary of State John Kerry in a telephone conversation that Palestinian militants had "unilaterally and grossly" violated the ceasefire and attacked Israeli soldiers after 9 a.m.

"Israel will take all necessary steps against those who call for our destruction and perpetrate terrorism against our citizens," Netanyahu told Kerry, according to a statement from the prime minister's office.