Israeli forces have demolished two apartment blocks in a Palestinian refugee camp in Gaza and have killed three men in a separate raid.
Israeli demolitions have been criticised as collective punishment
The army said the buildings in Khan Younis camp were used by Palestinian militants to launch attacks against Israeli soldiers and nearby settlers.
Israel's government meanwhile says it will attack Syria if necessary.
This follows the suicide bombings in Beersheba on Tuesday, which killed 16 people and injured 80.
Syria has rejected the warning. The Syrian foreign minister, Farouk Shara, said the threats were not based on any evidence and lacked all credibility.
Israeli tanks and bulldozers entered the Khan Younis refugee camp during the night.
They surrounded 10 apartment buildings and ordered hundreds of Palestinians to leave their homes.
Residents said the tanks fired shells at the buildings before telling the Palestinians to leave.
Soldiers then demolished two of the buildings which the army said had been used to fire mortars, rockets and anti-tank missiles at Israeli forces and the nearby Jewish settlements of Gush Katif and Neve Dekalim.
Helicopters fired missiles into the camp, wounding six Palestinians.
The Israeli forces pulled out just before dawn. Reports say dozens of Palestinian families were left homeless.
Palestinians and human rights groups criticise as collective punishment the Israeli tactic of demolishing houses which it says are used to launch militant attacks.
But military sources said the demolitions were not in response to the bus bombings by Hamas militants in the southern Israeli town of Beersheba on Tuesday.
In a separate raid on the Palestinian town of Deir al-Balah, Israeli troops fired on a crowd throwing stones, killing three Palestinian men, aged between 15 and 19, Palestinian hospital workers said.
Israel's military said the clashes erupted after it uncovered a tunnel from the town leading to a Jewish settlement.
According to the army, the soldiers opened fire after explosives were used against them.
Israel's Deputy Defence Minister Zeev Boim said that nobody was immune from Israeli reprisals if they attacked Israel.
He recalled the Israeli air strikes on Syrian territory last year, which followed an earlier Palestinian suicide bombing in Israel.
Mr Boim said that by choosing the right targets, Israel could, as he put it, impose the necessary red lines without risking a major conflagration.
"The rule that anyone who deals in terror against Israel is a target is a rule that must be stated and one that we must stand behind," Mr Boim said.
His comments follow accusations by Israeli politicians that Syria is harbouring leaders of Hamas, the Palestinian group that said it carried out the Beersheba bombings.