Palestinian medics said Saturday that one person was killed and three others were wounded during an Israeli strike on Gaza City's Zeitun neighborhood.
The injured Palestinians were evacuated to Gaza's Shifa Hospital.
The IDF denied carrying out an attack on the Hamas-ruled territory. Army officials estimated that the blast was the result of a failed attempt by Islamic Jihad terrorists to launch a rocket towards Israel.
According to some reports from Gaza, the four were hit by IDF artillery fire while sifting through rubble for steel and cement to recycle, but other reports said a dud caused the explosion.
Adham Abu Selmeya, spokesman for medical services in Gaza, issued a statement saying the blast was an Israeli tank shell.
Palestinian medical services claimed the IDF struck in response to rocket fire emanating from Gaza.
On Friday a mortar fired from the Strip landed in the western Negev, but no injuries or damage were reported.
On Tuesday a 17-year-old Palestinian was killed from IDF fire in north Gaza. Three other Palestinians were wounded. The IDF said it had fired an artillery shell at terrorists who approached the security fence, apparently to plant explosives.
Hanan Greenberg and Reuters contributed to the report