The source said the officers were hurt when two vehicles exploded in the car park of the police station in the eastern town of Ajdabiya.
The station houses Ajdabiya's surveillance control centre, and may have been targeted after last week's killing of General Abdelmajid al-Zwei by three gunmen was caught on camera, the source added.
Signup to our newsletter and follow us on Facebook and Twitter!
Zwei was a prominent commander in the anti-Islamist forces of general Khalifa Haftar, whose loose coalition has been waging a government-backed campaign against militias to wrest back control of Libya's second city Benghazi.
At least 356 people have been killed since the offensive was launched in October, according to medical and security sources.
Ajdabiya, 160 kilometres (100 miles) south of Benghazi, has largely avoided the violence that has plagued much of Libya since the NATO-backed toppling of former dictator Moamer Kadhafi in 2011.