As the Israeli military pounded central and southern Gaza by land, sea and air, Palestinian authorities reported scores of casualties and the United Nations health agency said thousands of people were trying to flee the widening offensive.

Residents in the central Gaza Strip said that with nightfall, Israeli tank shelling intensified on Wednesday east of the already overcrowded Bureij, Maghazi and Nuseirat refugee camps where tanks have been trying to force their way through.

Israeli army spokesperson Daniel Hagari said that additional reinforcements have been sent into the southern part of the Palestinian territory on the outskirts of Khan Younis.

Israeli forces were pressing on with their operations in the northern part of the enclave, leaving hundreds of thousands of fleeing Palestinians with no safe place left to shelter.

The World Health Organization (WHO) said its staff had seen thousands of people fleeing heavy strikes in Khan Younis on foot, on donkeys or in cars. Makeshift shelters were being built along the road.

“WHO is extremely concerned this fresh displacement of people will further strain health facilities in the south, which are already struggling to meet the population’s immense needs,” said Rik Peeperkorn, WHO representative for the occupied Palestinian territories.

“This forced mass movement of people will also lead to more overcrowding, increased risk of infectious diseases and make it even harder to deliver humanitarian aid.”