Israeli troops entered Gaza under cover of darkness on Saturday, escalating the war on Hamas after artillery pounded the Palestinian territory and warplanes staged dozens of air strikes -- one killing 16 people in a mosque.
"Large numbers of forces are taking part in this stage of the operation including infantry, tanks, engineering forces, artillery and intelligence," a military spokesman said.
The air force and navy were supporting the operation in the Hamas-controlled territory, the military spokesman added.
Thousands of Israeli troops and tanks had encircled Gaza as Howitzers lobbed shells across the border hours earlier. F-16 jets roared over the enclave where at least 460 people have been killed in eight days of attacks.