Israeli army spokesperson Daniel Hagari provided more details on the two dozen troops killed on Monday– the deadliest since the Gaza ground incursion began, Al Jazeera reported.

Hagari confirmed 21 Israeli soldiers were killed in an incident in central Gaza.

“An RPG [rocket-propelled grenade] was fired at a tank and simultaneously an explosion occurred at two two-story buildings,” Hagari said of battles near the Israeli boundary settlement of Kissufim.

The buildings were full of landmines that Israeli troops planted to demolish the Palestinian structures.  “The buildings collapsed due to this explosion while most of the forces were inside and near them,” said Hagari.

Three other Israeli troops died in fighting in southern Khan Younis.