The naval phase of Russia's Vostok-2010 military exercises have drawn increased attention from the intelligence services of the United States and Asia-Pacific countries, a senior source in the Russian Navy said on Tuesday.

The Russian Armed Forces started early last week large-scale Vostok-2010 military exercises in Siberia and the country's Far East. The drills, which involve at least 20,000 troops, up to 70 warplanes and 30 warships, will continue through July 8.

Increased activity by intelligence aviation, particularly Japanese, has been noticed in close proximity to the area where the drills are being held, the source said.

Attempts to collect data about the actions of the Pacific fleet were held from water and air, he added.

"This was not a surprise for the Pacific fleet," the source said, adding that intelligence-gathering operations had not disrupted the drills.

VLADIVOSTOK, July 6 (RIA Novosti)