Motorcycle-borne militants lobbed two grenades at the gate of a high-security military complex at Risalpur in northwest Pakistan on Tuesday, injuring 12 people, including four security personnel.
The militants struck at a time when a large group of youths were present at the gate to register for a recruitment drive, witnesses and police officials said.
They hurled two grenades and immediately fled from the spot.
Police officials said four security personnel and eight civilians were taken to nearby hospitals with minor injuries.
All the injured were out of danger and several of them were discharged after being provided first aid, they said.
The gate for the military complex on the G T Road leads to the Nowshera Cantonment, the Pakistan Air Force academy and several army training facilities.
Security forces, including army troops, cordoned off the area and launched a search operation but were unable to make any arrests.
DSP Muhammad Riaz Khan told reporters that several roadblocks had been set up and additional forces deployed in the area.
No group claimed responsibility for the attack though such incidents are usually blamed on the Pakistani Taliban.