Israel's repeated attacks on school buildings are condemned by Germany and France, who demand swift investigations.
On Wednesday, 20 Palestinians were killed in new airstrikes in Gaza – at the same time as Israel signals a continued intense offensive.
The Israeli army is urging residents of Gaza City to evacuate via thousands of flyers. On the papers, addressed to "all in Gaza City", escape routes southward are marked.
The warning comes at a time when Israeli soldiers, backed by tanks and aircraft, are stepping up their offensive in the city against Hamas and Islamic Jihad. The area has suffered the heaviest fighting in months.
On Wednesday, reports emerged of an Israeli attack on the long-abandoned UN agency Unrwa's headquarters in the city. The Israeli military claims that the building was used by Hamas and says it found large quantities of weapons on site.
In other parts of the Gaza Strip, 20 Palestinians were killed in Israeli airstrikes early on Wednesday morning, according to the health authorities on the Hamas-controlled coastal strip.
Several children killed
Among the dead are six children and three women. Some of the victims were reportedly in the "safe zones" where Israel's military had urged Palestinians to seek shelter during the offensive in Gaza.
Twelve of the victims died in attacks on three houses in Nusseirat, which has functioned as a refugee camp for displaced Palestinians since 1948. A reporter from the AP news agency counted the bodies at a local hospital.
The attacks came just hours after Tuesday's deadly attack on a school building near Khan Yunis in southern Gaza. A total of 31 people have been confirmed dead – including eight children – according to reports from the nearby Nasser hospital. On Al Jazeera footage, children can be seen playing soccer in the schoolyard when a sudden explosion rocks the area.
Israel's military claims it targeted a "terrorist" in the area and will investigate the incident further.
Sharp criticism
The attack follows three earlier Israeli attacks since Saturday on school buildings around Gaza used as shelters by displaced Palestinians. At least 20 people were killed in those attacks, according to health authorities.
Germany and France are directing sharp criticism at the attacks.
"It is unacceptable that schools, especially those housing civilians displaced by the fighting, are being attacked", the French Foreign Ministry writes in a statement, calling for a thorough investigation.
So does Germany.
"The repeated attacks on schools by the Israeli army must stop and an investigation must be launched swiftly", is the message from Berlin.
The Islamist extremist group Hamas attacked Israel on the morning of Saturday, October 7, last year. Around 1,150 people are estimated to have fallen victim to the terrorist attack, most of them civilians, and more than 200 people were taken hostage.
Israel responded by declaring war. It has besieged Gaza, bombed the coastal strip continuously, and sent in ground troops with the stated aim of destroying Hamas.
According to Hamas-controlled authorities, more than 38,000 people have been killed in Israeli attacks in Gaza since the outbreak of war. Large parts of the area's infrastructure have been razed to the ground. Aid organizations are repeatedly sounding the alarm about severe famine and an escalating humanitarian crisis.
More than 100 people are still being held hostage in Gaza, according to Israel, since around the same number were released in exchanges and a few more were rescued. Many of those still held are feared to no longer be alive.
