The health ministry in Hamas-controlled Gaza said an explosion in a refugee camp near Rafah killed 50 people and injured dozens more.
The Israel Defense Forces (IDF) confirmed it carried out air strikes on Hamas compounds in the area. It said the incident was under review.
Earlier in the day, Hamas fired eight rockets from Rafah into Tel Aviv, its first long-range attack on the city since January.
Video from southern Gaza showed massive explosions and fierce fires.
Hamas said Israeli airstrikes hit a Palestinian displaced persons camp northwest of Rafah, far from recent military operations in the designated humanitarian safe zone.
Women and children were said to be among the dead.
The Israel Defense Forces confirmed they were targeting Hamas militants in the area and said they were aware of reports of attacks sparking fires and injuring civilians.
It is reviewing the incident but said it used precision weapons against legitimate targets.
early sunday Air raid sirens sound around Tel Aviv Central Israel came under fire from Hamas rockets fired from near Rafah.
The eight rockets were either intercepted by air defense systems or fell into fields.
Despite Israeli military offensive against Rafah continues The International Court of Justice ruled on Friday that it must stop.
Although no injuries were reported, the rocket attack highlighted the threat Hamas still poses to people across Israel.
It also illustrates the challenges faced by Israeli forces as they push deeper into southern Gaza to drive Hamas out of what it calls its “last major stronghold.”
The rocket attack came ahead of further ceasefire talks between Israel and Hamas, which are expected to resume next week.
Hamas’ military wing said its actions were in response to “the massacre of civilians”.
Israel’s military operation in Gaza began on October 7 after Hamas-led gunmen attacked Israel, killing about 1,200 people and taking another 252 people back to Gaza as hostages.
Nearly 36,000 Palestinians have been killed in the war since then, according to the Gaza health ministry, which is run by Hamas.
