An explosion in Cairo on Monday killed two policemen who were chasing a man believed to have targeted security staff near a mosque last week, Egypt's interior ministry said.
"As security surrounded the man and was set to arrest and control him, an explosive device in his possession went off," the ministry said.
The blast in the crowded Darb al-Ahmar district in downtown Cairo also killed the bomber and injured three other policemen.
The man was being pursued as part of "efforts to search for the perpetrator" responsible for planting an explosive device near security staff close to a mosque in Giza on Friday, the ministry said.
Security had been able to defuse that device, the ministry said.
Monday's explosion took place near Al Azhar mosque at the heart of ancient Islamic Cairo, damaging several shops.
The site was cordoned off and reporters were not immediately allowed access to the area.
"My shop's front and windows were destroyed," said Kareem Sayed Awad, a barbershop owner. "Not only that, but people have died. This is a tourist area and such incidents affect it."