MAKHACHKALA, April 23 (RIA Novosti) - One officer was injured after an unknown assailant threw a hand grenade at a traffic police post in Makhachkala, the capital of the Russian southern republic of Daghestan.

A source in the Russian Interior Ministry said the incident occurred late on Tuesday when the officers were on duty. The search for the attacker, who fled the scene, is ongoing.

No other explosives were discovered in the area.

Although the active phase of the antiterrorism campaign in the North Caucasus officially ended in 2001, periodic bombings and clashes between militants and federal troops still disrupt the region, in particular Daghestan, Chechnya and Ingushetia.