Egypt's Interior Ministry says a man was killed and three members of his family were injured when a device exploded while he was cleaning up his backyard in a leafy Cairo suburb.
The police didn't elaborate on whether the device is a bomb and they could not specify what exactly triggered the blast on Friday.
The ministry says the blast occurred in the southern residential suburb of Maadi that is also home to many diplomatic residences in the Egyptian capital.
The statement added that security forces have cordoned off the area. No further details were immediately available.
Egypt has seen an increase in militant attacks in the past years, mostly in the restive Sinai Peninsula where the military is carrying out a campaign against an Islamic State affiliate.