(Reuters) - A detachment of Russia's navy warships returned from more than three weeks of joint-patrolling of the Pacific Ocean with Chinese navy ships, the Russian Interfax news agency reported on Sunday.
Warships of Russia's Pacific Fleet, together with a detachment of Chinese navy ships travelled more than 7,000 nautical miles through the Sea of Japan, the Sea of Okhotsk, the Bering Sea and the Pacific Ocean, Interfax reported citing the Fleet's press service.
During the patrol, the Russian-Chinese detachment passed along the Kuril ridge, the agency reported.
The islands, off the northern Japanese island of Hokkaido, are known in Russia as the Kurils and in Japan as the Northern Territories and have been at the core of decades of tension between the neighbours.
The Russian-Chinese warships also circled part of the Aleutian Islands archipelago. Most of the Aleutian Islands belong to the U.S. state of Alaska, but the Commander Islands near the Kamchatka Peninsula are part of Russia.
The Wall Street Journal reported in early August that 11 Russian and Chinese ships steamed close to the Aleutian Islands, in what appeared to be appeared to be the largest such flotilla to approach American shores.
The ships never entered U.S. territorial waters, the newspaper reported, citing U.S. officials.
Interfax on Sunday reported that some of the Pacific Fleet's largest warships participated in the patrol.
"During the patrol, joint anti-submarine and anti-aircraft exercises were carried out, a search was made for submarines of a mock enemy using helicopters and aircraft of naval aviation from both sides, mock missile firing was carried out at a detachment of mock enemy ships," the agency reported.
(Reporting by Lidia Kelly in Warsaw; Editing by Christopher Cushing)