It said its land force was small and had been deployed as a deterrent.
At least three militants were killed in four separate air raids, one of which targeted Hamas offices in
The Israeli attacks came as fighting eased between Palestinian factions Hamas and Fatah. It has left at least 40 people dead in the past five days.
Correspondents say the rocket attacks into
Palestinian Authority President Mahmoud Abbas, who leads Fatah, on Thursday suddenly called off a trip to
Officials said he might now travel from Ramallah in the
The BBC's Magdi Abdelhadi says control of the security forces appears to have been the trigger for the latest factional fighting but that it has now developed a momentum of its own.
Armed supporters on the ground may no longer be paying attention to orders from their political leadership, he says.
On Thursday in
Series of strikes
A military spokesman said the force was on a "defensive operation".
The move came after Hamas militants fired more rockets at the southern Israeli town of
The BBC's Middle East correspondent Tim Franks, who is in Sderot, said many people there were demanding the Israeli military take robust action inside
The military earlier confirmed four air strikes in
One destroyed the second floor of a two-storey building belonging to the Executive Force, a militia force with the task of maintaining security in
Hamas's armed wing threatened to renew self-sacrifice bombings in
The second air attack targeted a car carrying militants in
One Hamas militant was killed in the third attack - on a housing unit for security guards of a senior Hamas official.
'Shameful'
On Thursday morning, factional gun battles broke out in the southern
A pro-Fatah gunman was said to have been killed. However clashes were reported to be lighter overall.
The fighting between Mr Abbas's Fatah and the Islamist Hamas threatens a hard-won unity government they formed in March.
Information Minister Mustafa Barghouti - one of the Palestinian cabinet's independent members - described the violence as shameful.
Photo caption
Hamas office in