China’s Defense Ministry denied allegations by Japan on Friday that a Chinese frigate locked its radar on a Japanese navy ship in the East China Sea last week.

China’s Defense Ministry issued a statement saying Tokyo’s remarks were “against the facts,” adding that Japanese surveillance routine was “the root cause of air and maritime safety issues” between the two countries.

Japan’s Defense Minister Itsunori Onodera announced on Tuesday that “something like fire-control radar was directed at a Japan Self-Defense Force Maritime escort ship in the East China Sea” on Jan. 30. He said similar radar was aimed at a Japanese military helicopter on Jan. 19.

Japan's Foreign Ministry also lodged a protest with the Chinese embassy in Japan on Tuesday.

The Chinese Defense Ministry statement said on both of the days in question, the Chinese naval ships “kept normal observation and alert, and fire control radar was not used.”

The statement accused Tokyo of releasing “untrue information to the media” and “recklessly” creating tension and “misleading international public opinion.”

Japan’s Prime Minister Shinzo Abe described the radar lock incident as a “one-sided provocation” on Wednesday, claiming that it could have led to an "unpredictable situation.”

The dispute between Japan and China over a tiny group of uninhabited islands, known as the Senkaku Islands in Japan and the Diaoyu Islands in China, escalated on Sept.11, when the Japanese government announced it signed a contract worth 2.05 billion yen ($26 million) to buy three of the five disputed islands from their private owner. Since then Chinese patrol ships have frequented the waters around the islands.

The islands, which lie some 200km (124 miles) off Japan's Okinawa island and beyond China's 200 nautical mile (370km) exclusive economic zone, are surrounded by an area rich in fisheries and are believed to contain significant hydrocarbon resources.