Israeli Prime Minister Benjamin Netanyahu praised the "superior intelligence" of the Shin Bet security service and the military's "precise execution" of the attack.
An Israeli defence official said that ten thousand reserve soldiers would be called up for duty.
The killing of the three Hamas commanders will likely buy Netanyahu some time as the Israeli public becomes increasingly impatient with the Government's inability to halt rocket fire from Gaza.
Gaza police and witnesses said several missiles hit the four-storey building.
In pinpointing the whereabouts of the Hamas commanders, Israel probably relied to some extent on local informers. Israel has maintained a network of informers despite its withdrawal from Gaza in 2005, in some cases using blackmail or the lure of exit permits to win co-operation.
Al Majd, a website linked to the Hamas security services, said yesterday that seven suspected informers were arrested in recent days and that three were killed "after the completion of the revolutionary procedures against them".
It was the second time during the Gaza war that the website announced suspected informers had been killed by Hamas.
The Rafah attack came a day after an apparent Israeli attempt to kill the top Hamas military leader, Mohammed Deif, in an air strike on a house in Gaza City. Deif's wife and an infant son were killed in that strike, but the Hamas military wing said Deif was not in the targeted home at the time.
The body of his daughter, 5-year-old Sara Deif, was recovered from underneath the rubble yesterday.
The back-to-back targeting of top Hamas military leaders came after indirect Israel-Hamas negotiations in Cairo on a sustainable truce broke down on Tuesday.
Gaza militants resumed rocket fire on Israel, even before the formal end of a six-day truce.
Since then, Gaza militants have fired dozens more rockets, and Israeli aircraft have struck dozens of targets in Gaza.
- Independent
