TOKYO, July 5. /TASS/. Three Russian warships have passed through an area off the Senkaku Islands (Diaoyu Dao) in the East China Sea, which are claimed by both Tokyo and Beijing, the Joint Staff of the Japanese Self-Defense Forces said on Tuesday.

The three warships passed through the strait between two islands of the Senkaku archipelago on Monday evening and headed for the northern part of the East China Sea, the agency said. They didn’t violate any rules. Their movement was observed by destroyers and a patrol aircraft of the Maritime Self-Defense Forces.

On Monday, Japan's Ministry of Defense said that a Russian Navy ship had passed the zone adjacent to the water area around the Senkaku Islands. On the same day, a Chinese warship entered the area for the first time since June 2018. That prompted Tokyo to express an official protest to Beijing, while to Moscow Japan expressed concern through diplomatic channels.

The dispute over the Senkaku Islands escalated after Tokyo announced in September 2012 that it was buying them from private owners who are Japanese citizens. After that, mass protests took place in China. Since then, Chinese ships have been constantly passing near the disputed archipelago and making demonstrative entries to its coastal zone.