Hamas has said it is engaged in “heavy fighting” with Israeli troops inside northern Gaza, as besieged residents were again warned to flee southward, AFP reports.

Late Sunday Israel’s military released footage that purported to show a significant number of tanks, infantry, and artillery operating in Palestinian territory.

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”.