Two Russian Su-24M attack jets made extremely close passes on a the HNLMS Evertsen, a Dutch air defense frigate, on Tuesday, according to the Dutch navy.

The Russian jets got within 200 meters of the ship, though it's not immediately clear if they were armed. The Dutch frigate has advanced radars and surface to air missiles, but the Dutch navy maintains it did not see the Russian jets as a threat.

The passage was not a threat to air defense and command frigate. However, the operations were monitored closely. This was done by the frigate, but also by the two fighters from the Swedish Quick Reaction Alert that accompanied the Russians.

The Sukhoi Su-24 (NATO reporting name: Fencer) is a supersonic, all-weather attack aircraft. The aircraft has a variable-sweep wing, twin-engines and a side-by-side seating arrangement for its two crew.

The Su-24M front-line attack aircraft is designed to penetrate hostile territory and destroy ground and surface targets in any weather conditions, by day and night. Variants of the Su-24 have also been produced, designed for reconnaissance and electronic countermeasures.