Israeli tanks on Monday rolled into a part of central Gaza that has not previously seen ground operations in the 21-month war, according to Israeli media, aid agencies and witnesses.

Tens of thousands of people were warned to flee the city, where many displaced Palestinians have been sheltering and it's thought some Israeli hostages are held.

The area is packed with Palestinians who left their homes during 21 months of war in Gaza, hundreds of whom fled west or south after Israel issued an evacuation order on Sunday. Israeli tanks pushed into the southern and eastern districts of the Gazan city of Deir al-Balah on Monday,