Two Russian warships conducted a tactical air-defense exercise in the eastern part of the Indian Ocean on Thursday.

The Moskva guided-missile cruiser, the flagship of the Black Sea Fleet, teamed up on Sunday with the Northern Fleet's flagship, the Pyotr Veliky nuclear-powered guided-missile cruiser, and began a series of exercises in the Indian Ocean on Tuesday.

According to the exercise scenario, aggressor helicopters launched an air assault, which was repulsed with "virtual (electronic) fire."

After that, the Russian warships fired live rounds at a simulated air target, "virtually engaging" it.

On Wednesday, they responded to a simulated nuclear attack with elements of chemical, biological and radiological (CBR) warfare and helped a vessel in distress following a nuclear explosion.

Tuesday's exercise involved a rescue at sea, extinguishing a fire on board a vessel in distress and towing it to safety.

The two vessels are due to arrive in Russia's Far Eastern port of Vladivostok in June-July to take part in the Vostok-2010 large-scale strategic exercise.

The exact date of the drills has yet to be announced.

Russia announced in 2007 that it was building up its naval presence throughout the world, and foreign port calls by Russian warships have become more frequent.

RFS PYOTR VELIKY, May 6 (RIA Novosti)