Militants in Gaza say they have not captured a missing Israeli soldier, and have warned that he may have been killed.
Israel says 23-year-old Hadar Goldin was snatched during fighting yesterday as the ceasefire there dramatically collapsed.
Hamas denies taking him.
Officials in Palestine said 37 of those killed died in Israeli strikes on Rafah, where the soldier, Hadar Goldin, went missing.
A series of rocket attacks into Israel were also reported on Saturday morning.
The armed wing of Hamas says it had "lost contact" with Islamist militants operating in a region of southern Gaza where the soldier was apparently taken.
In a statement the group said it believes the militants were all killed by Israeli "bombardment" on Friday, and that the missing soldier may also have died.
"We have lost contact with the group of fighters that took part in the ambush and we believe they were all killed in the (Israeli) bombardment," the statement said.
"Assuming that they managed to seize the soldier during combat, we assess that he was also killed in the incident."
Israel claims 23-year-old Second Lieutenant Hadar Goldin was kidnapped on Friday just 90 minutes into a three-day ceasefire, which has now collapsed.
Two other Israeli soldiers were killed when Second Lieutenant Goldin was apparently abducted after gunmen emerged from tunnel openings and opened fire.
Israel says at least one of the Hamas fighters blew himself up with an explosives belt before Second Lieutenant Goldin was dragged into a tunnel.
Both Israel and Hamas accuse each other of breaking the three-day ceasefire, which was announced by the US and the UN late on Thursday and began at 8am (6am Irish time) on Friday.
Meanwhile, for the fourth Saturday in a row protests against the Israeli assault on Gaza are planned across Ireland.
The biggest protest is expected to be in Dublin, starting at the Garden of Remembrance at 2pm and marching from there to the Department of Foreign Affairs.
The protests are being organised by the Ireland-Palestine Solidarity Campaign and supported by the Irish Congress of Trade Unions, SIPTU and the Trade Union Friends of Palestine.
