More than 20 people were killed in an attack on a tent camp north of Rafah in the Gaza Strip. The International Committee of the Red Cross (ICRC), which operates a field hospital nearby, reported at least 22 dead and 45 injured. The Health Ministry, controlled by the militant Islamist Hamas, reported 25 dead and 50 injured.

It was not immediately clear who was responsible for the attack. The Israeli military said it was investigating the case based on the coordinates provided. According to an initial investigation, there was no direct attack on a Red Cross facility, the military announced on Saturday evening.

The ICRC announced on Platform X that “heavy caliber” projectiles had hit the area. According to the report, hospital staff were also living in the tents near the field hospital.

Ahmed Radwan, spokesman for the first responders of the Hamas-controlled civil defense in Rafah, said witnesses told rescuers that at least two locations near the coast had been shelled. The tent camp that was shelled was just outside a security zone designated by Israel.

Eyewitnesses whose relatives were killed in the shelling also told the AP news agency that many people came out of their tents after the first shell hit. Then a second volley hit near the field hospital.

Hasan al-Najjar said his sons were killed while helping people who had panicked after the first attack. “They went to save the women and they hit with the second projectile and my sons were killed,” he said. “They hit the place twice.”

Mona Ashur said the first attack only produced a loud bang and a bright glow. Her husband went out of the tent to see where the noise was coming from and was killed in the second attack.

Israel has previously bombed sites near the “humanitarian zone” in Al-Muwasi, a rural area on the Mediterranean coast where extensive tent camps have been set up in recent months. Less than a month ago, an Israeli attack sparked a fire in a camp for displaced Palestinians, killing at least 45 people, according to Palestinian sources.

Israel has said it is targeting Hamas fighters and the militant Islamist group’s infrastructure and is trying to cause as little harm to civilians as possible. The high number of civilian casualties is due to the fact that Hamas operates from among the civilian population. The army is making considerable efforts to prevent harm to workers and facilities of international organizations in the Gaza Strip, the military said in a statement on Saturday.