Israeli tanks advanced into the heart of Gaza City from different directions on Monday and Israel ordered Palestinian civilians to evacuate neighbourhoods after a night of bombardments which Gaza authorities said had killed dozens.

Residents said the airstrikes and artillery barrages — which took place as multi-national talks for a ceasefire deal intensified — were among the heaviest attacks on the Gaza Strip in nine months of conflict between Israeli forces and Hamas militants.

Gaza City was one of the first areas that Israeli troops moved into at the start of the war. But fighting with militants still holding out there has persisted and civilians have sought shelter elsewhere, adding to multiple waves of displacement.

Residents said neighbourhoods of Gaza City had been bombed throughout the night into the early morning hours. Several multi-storey buildings have been destroyed, they said.

The Gaza Civil Emergency Service said it believed dozens of people were killed but emergency teams were unable to reach them because of ongoing offensives in Daraj and Tuffah in the east and Tel Al-Hawa, Sabra and Rimal further west.

Gaza residents said tanks advanced from at least three directions on Monday and reached the heart of Gaza City, backed by heavy Israeli fire from the air and ground.

That forced thousands of people out of their homes to look for safer shelter, which for many was impossible to find, and some slept on the roadside. One tank thrust pushed people towards the western road near the Mediterranean, residents said.

“The enemy is behind us and the sea is in front of us, where we will we go?” said Abdel-Ghani, a Gaza City resident who did not give his full name.