At least 13 policemen and three civilians were wounded when an explosive device went off near a police training center in the Nile Delta city of Tanta on Saturday, Egypt's ministry of interior said.
The bomb was planted in a motorcycle parked near the center and the area has been cordoned off and is being combed by security forces, a ministry statement said.
The injured have been moved to a hospital nearby for treatment. Two of them are in critical condition, a Ministry of health spokesman said.
There was no immediate claim of responsibility.
The government is battling militants loyal to Islamic State in the Sinai Peninsula and other Islamist groups elsewhere in the country who generally target security forces.