The Israeli military has pummeled the UN-run Al-Fakhoura school, in a renewed strike that has left over 50 people dead, according to Gaza's health ministry.

Two Israeli airstrikes that struck the city of Khan Younis this morning killed dozens of people, with scores injured and/or buried under the rubble. Another airstrike in Deir el-Balah in central Gaza killed six, with many others wounded.

Shocking footages obtained by PRC appeared to show the tragic upshots of the onslaught on al-Fakhoura, a United Nations-run school which had been converted into a shelter for displaced Palestinians.

Bodies are seen motionless on the ground, lying in what appears to be pools of blood amid mounds of rubble from which voices of trapped civilians can be heard.

Denouncing the 'horrifying images and footage of scores of people killed and injured' in the school, UNRWA chief Philippe Lazzarini said such attacks 'cannot become commonplace, they must stop'.

At least 32 people were killed in a separate attack on another building in the refugee camp during overnight strikes.

More than 80 people were killed in total during twin strikes on the Jabalia refugee camp, a health ministry official in the Gaza Strip said today.

Jabalia, in the northern Gaza Strip, is the biggest refugee camp in the Palestinian territory, where some 1.6 million have been displaced by more than six weeks of fighting between Israel and Hamas.

Earlier this month, the health ministry said 15 people were killed by a strike at the same school.

UNRWA said four of its schools in the Gaza Strip housing people displaced by the war had been damaged by bombings.

A separate strike on another building in the Jabalia camp on Saturday killed 32 people from the same family, 19 of them children, the health ministry reported.

Many have taken refuge in schools and hospitals afforded special protections under the rules of war. But packed into one of the world's most densely-populated urban areas, many civilians have been caught in Israeli bombing.