Israel returned the bodies of more than 80 Palestinians killed in its military offensive in the Gaza Strip, as Israeli airstrikes killed at least 18 more people on Monday, the Palestinian Ministry of Health said.

Yamen Abu Suleiman, the director of the Palestinian Civil Emergency Service in Khan Younis in southern Gaza, said it was unclear whether the bodies had been dug up from cemeteries by the army during the ground offensive, or whether they were "detainees who had been tortured and killed."

"The occupation provided us with no information about the names, or ages, or anything. This is a war crime, a crime against humanity," Abu Suleiman said.

The bodies will be screened and examined in an attempt to determine the causes of death and in an attempt to identify them. They will later be buried in a mass grave at a cemetery near Nasser Hospital in Khan Younis.

The 84 bodies arrived in more than 15 bags, each containing several bodies, Abu Suleiman added.

There was no immediate comment from the Israeli military on the return of the bodies. In the past, Israel has said it returned bodies after checks they were not Israeli hostages who had been held by Hamas since the Oct. 7 attack on Israel.