China Coast Guard vessels have been spotted near the Japanese-administered Senkaku Islands for a record 353 days this year, the Japan Coast Guard (JCG) said Sunday, as Beijing continues to ramp up its activities near the tiny islets that it also claims.

As of midnight Monday, four China Coast Guard vessels had been confirmed inside the so-called contiguous zone just outside Japan’s territorial waters around the Senkakus, the JCG said.

“The circumstances in the waters surrounding the Senkaku Islands remain severe and unpredictable,” Seishiro Sakamoto, director-general of the JCG's 11th regional headquarters, said a statement.