MOSCOW, August 16 (RIA Novosti) - Two police officers were killed and two more wounded over the past 24 hours in various districts of Russia's North Caucasus republic of Chechnya, a police source said on Saturday.

The source said that unknown suspects opened fire on a police patrol late on Friday night in the Nozhai-Yurt district of Chechnya, lethally wounding one of the officers, who later died in hospital.

On early Saturday, unknown assailants driving two cars opened fire on another police patrol in the Urus-Martan district killing one officer and wounding two more.

Although the active phase of the antiterrorism campaign in Russia's North Caucasus officially ended in 2001, periodic bombings and clashes between militants and federal troops still disrupt Chechnya and nearby regions, including Ingushetia.