Hamas said it was engaged in "heavy fighting" with Israeli troops inside northern Gaza Sunday, as besieged residents were again warned to flee southward, reports BSS.
After weeks of ferocious airstrikes, Israel has declared a new "stage" in a war that Prime Minister Benjamin Netanyahu warned would be "long and difficult".
Late Sunday Israel's military released footage that purported to show a significant number of tanks, infantry and artillery operating in Palestinian territory.
The military claimed to have struck more than "450 terror targets, including operational command centres, observation posts, and anti-tank missile launch posts".
Hamas said its Ezzedine al-Qassam Brigades were already "engaged in heavy fighting... with the invading occupation forces".
With a fierce door-to-door urban war expected, Israeli army spokesman Daniel Hagari told Palestinian civilians to go south "to a safer area".
It is now 23 days since Hamas gunmen launched a wave of bloody cross-border raids against homes, communities, farms and security posts inside Israel.
An estimated 1,400 people, mostly civilians, were killed and 239 people were taken hostage, according to the latest Israeli tallies.
Israel has vowed to free the hostages, track down those responsible and "eradicate" Hamas, a Palestinian Islamist movement that has governed Gaza since 2007.
But there is deep and growing international concern about the toll of Israel's campaign on Gaza's two-plus million residents.
The territory is under siege, with people unable to leave and only a limited amount of humanitarian aid allowed in.
Meanwhile, Israel has carried out one of the most intense bombing campaigns in recent memory.
The Hamas-run health ministry in Gaza says more than 8,000 people, mainly civilians and half of them children have already been killed.
Bd-pratidin English/Tanvir Raihan
