The funerals have taken place of three top Hamas commanders killed in Israeli air strikes.
The processions drew thousands of mourners in the southern Gazan city of Rafah.
The commanders’ bodies were draped in the flag of Hamas’ military wing.
There were calls for revenge and Hamas described the assassinations as a “grave crime”, saying Israel would “pay the price”.
The three commanders were identified as Mohammed Abu Shamaleh, Raed Attar and Mohammed Barhoum. They are said by both sides to have played key roles within Hamas.
Israel said they were involved in digging tunnels, training fighters and smuggling weapons to Gaza.
The Islamist movement said they’d led operations against Israel for 20 years.
The Israeli military and Shin Bet, the internal security service, confirmed it had targeted two of the men.
Following the collapse on Tuesday of a 10-day ceasefire, the Israeli military appears to have ramped up its efforts to hit the leadership of Hamas’ armed wing.
Late on Tuesday, the Israeli air force bombed a house in northern Gaza, an attempt, Hamas said, to assassinate Mohammed Deif, its top military commander. Deif’s wife, daughter and seven-month-old son were killed but Deif escaped, Hamas said.
The military figures were not the only victims of Israeli air strikes on Thursday.
In Gaza City at least four members of the same Palestinian family – three children along with their father – were killed.
Distressed relatives accompanied their bodies as they were taken to a nearby morgue.
Palestinian health authorities said that the day’s air strikes had left 26 people dead in all.
Tel Aviv’s Ben Gurion airport has functioned normally, despite threats by Hamas to target it.
The organisation had warned airlines to stay away and said it had fired a rocket towards the airport, but an Israeli spokesman said no disruptions were reported to flight schedules.
Many previous rockets have been shot down by Israel’s Iron Dome interceptor.