Israel intensified its offensive in southern Gaza early on Thursday, as tanks entered the territory from Israel and warplanes struck suspected tunnels in the Egyptian border city of Rafah, witnesses said.
Dozens of tanks, supported by several helicopters, entered Gaza at the Kisufim border crossing at around 04:30 am IST and were headed toward the city of Khan Yunis, witnesses told AFP.
The army could not immediately confirm that claim.
There were also unconfirmed reports that there had earlier been three air strikes on open areas near Khan Yunis.
Meanwhile, warplanes hit a house and a suspected tunnel in an open area near the Egyptian border, witnesses said.
The army, which had warned of an overnight bombing campaign, confirmed that strikes were taking place in Rafah.
There were no immediate reports of casualties in Rafah.
Israel, whose assault on Gaza is aimed at preventing the enclave's Hamas rulers from firing rockets into its territory, claims that the Islamist group is supplied with weapons through hundreds of tunnels coming from Egypt.
On Wednesday afternoon, Israeli planes dropped tens of thousands of leaflets on the Rafah area, warning people to leave their houses or face air strikes.
People were told that they could return to their homes at 1130 IST on Thursday.