The Civil Defense Agency in Gaza said at least 25 people were killed in Israeli strikes, including 15 who had gathered near an aid distribution center.
The agency's official, Mohammad al-Mughayyir, told AFP that 15 people were killed and 60 others were injured while waiting for aid in the Netzarim corridor, in central Gaza, where thousands of people gather daily in the hope of receiving food.
The Israeli military said it was investigating reports of deadly attacks near aid centers.
Bassam Abu Shaar, an eyewitness, said thousands of people had gathered overnight in the hope of receiving aid from the center - which is operated by a foundation backed by Israel and the United States - when it opened in the morning.
"Around 01:00 [local time], they started shooting at us. Then, the fire intensified from tanks and aircraft," he told AFP.
In recent weeks, dozens of Palestinians have been killed while trying to reach aid centers in Gaza.
In March, Israel imposed a general blockade on the entry of aid into the Palestinian territory and partially lifted it at the end of May.
Since then, the Humanitarian Foundation for Gaza – supported by Israel and the US – has begun distributing aid, and chaotic scenes have been seen in front of its centers.
United Nations agencies and other major aid organizations have refused to cooperate with the foundation, expressing concerns that it was created to help Israel achieve its military goals.
Elsewhere in Gaza, another ten people were killed by Israeli strikes on June 19, the Gaza Strip Civil Defense Agency said.
According to the agency, three were killed when a residential building in Gaza City was bombed and seven others after an airstrike on the Al-Shati refugee camp.
The war in Gaza began when militants led by Hamas — the Palestinian group designated a terrorist organization by the U.S. and European Union — attacked southern Israel, killing nearly 1,200 people and taking about 250 hostages. Israel says 58 hostages still remain in Gaza, although about 35 are believed to be dead.
Since then, Israel's war has killed more than 55,000 people in Gaza, many of them women and children, according to Palestinian health officials. (A2 Televizion)