At least nine people, including six policemen, have been killed in a bomb explosion during a raid on a militant hideout in the Egyptian capital, Cairo.
More than 13 others were injured, including the local police chief.
Security sources say the blast went off as officers raided an apartment in Giza, near the Pyramids.
The government has tightened security ahead of next week’s fifth anniversary of the uprising that removed long-time Egyptian President Hosni Mubarak.
The so-called Islamic State said it was behind the blast, while Egyptian authorities blamed the outlawed Muslim Brotherhood movement of former President Mohammed Morsi.
“Police had information that a group of Muslim Brotherhood members were preparing to carry out aggressive acts in the coming days using explosives and crude bombs,” the interior ministry said on its Facebook page.
“This group was using an apartment in a Cairo building, and on Thursday night the police raided this apartment where they found a number of crude bombs.
“When the bomb squad experts were dealing with one of the bombs, it exploded.”
The Brotherhood has denied any involvement in violence and says it is committed to peaceful activism.
One Giza resident, Khaled, said: “When the bomb exploded, it also destroyed parts of the building behind it. We saw a man who was blown up in his bed.
“I then looked at the other side. I found body parts all over the ground.”
Another resident, identified as Umm Sameh, whose home was damaged in the blast said: “No-one in the neighbourhood knew that they were terrorists. Had we known, we wouldn’t have left them alone.
“The building is still new. The residents have only been here for six months at the most. So, we really didn’t know them.”