A Canadian warship had a close encounter with Russian frigates just hours after arriving in the Black Sea to take part in NATO training exercises, CTV News has learned.

HMCS Fredericton had joined five other NATO vessels when two Russian warships appeared only three nautical miles from the NATO fleet.

The Russian ships trailed the NATO ships until they broke off into two groups, then went on their way.

HMCS Fredericton is participating in a month-long operation to improve maritime security in central and eastern Europe.

The Defence Department has said that the exercises are directly related to Russia's aggression towards Ukraine.

When HMCS Toronto took part in NATO exercises in the Black Sea last September, Russian military aircraft circled the warship in what the minister of defence called an “unnecessarily provocative” move.