How did two Gazans get injured this morning?

Ma'an (Arabic) says that several men were gathering debris near the Sufa crossing in southern Gaza, and they came across some old Israeli ordnance which exploded, causing two of them to be injured.

But Felesteen, a Hamas newspaper in Gaza, says

Eyewitnesses reported that members of the resistance fired a mortar towards a number of Israeli military vehicles at the Sufa crossing east of the town of Rafah, but it fell in near a group of workers collecting [concrete] aggregate resulting in their injury.

It then quotes a Hamas medical official - who obviously wasn't there - claiming that it was an Israeli tank shell, not "resistance" fire, that injured the men.