Israel says the seizure of territory in Gaza is aimed at pressuring Hamas to release hostages, but it is a major point of contention in ongoing cease-fire talks.

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.

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,

The Israeli military has issued new evacuation warnings for central Gaza, an area where ground operations have been rare. This move cuts access between Deir al-Balah and southern cities.

The Israeli military issued evacuation orders on Sunday in areas of central Gaza packed with displaced Palestinians where it hasn't operated so far in its war with Hamas, while medics said at least 30 people were killed waiting for aid as hunger mounts.

A U.N. official, speaking on condition of anonymity because they were not allowed to comment on the incident to the media, said Israeli forces opened fire toward crowds who tried to take food from the convoy.