Article Posted on : - Sep 16, 2012

An unrelated file photo.

TOKYO (AFP): Six Chinese ships sailed into waters around a disputed archipelago Friday, with Beijing saying they were there for "law enforcement" around islands Japan nationalised earlier this week.

The move -- dubbed "unprecedented" by Tokyo -- came as it was reported Japanese nationals had been physically attacked in China, marking the latest stage in a deteriorating row between Asia's two biggest economies.

Japanese living or visiting China were warned to take extra precautions after assaults and harassment were reported to the consulate in Shanghai, a base for Japanese businesses and a popular tourist destination.

Tokyo summoned the Chinese ambassador to protest what it insisted was an incursion into territorial waters around islands it controls, called Senkaku, but claimed by Beijing, which refers to the islets as Diaoyu.

However, China was resolute, with the foreign ministry issuing a forthright statement claiming the boats were patrolling sovereign territory.

"Two Chinese surveillance ship fleets have arrived at waters around the Diaoyu Islands and adjacent islands on September 14, 2012 to start patrol and law enforcement," the statement said.

"These law enforcement and patrol activities are designed to demonstrate China's jurisdiction over the islands and safeguard its maritime interests."

Japan's coastguard said the ships had all left the area by around 1:20 pm local time, approximately seven hours after the first vessel had arrived.

Japan's Chief Cabinet Secretary Osamu Fujimura said the foreign ministry summoned China's ambassador, Cheng Yonghua, to lodge a protest.

"We understand that (the dispatch of) six ships is surely an unprecedented case," he told a press conference.

Fujimura said Yonghua had reiterated Beijing's claims to the islands in the East China Sea, which lie around 400 kilometres from the Okinawan capital of Naha and 200 kilometres from Taiwan.

Japan urged "that China do its utmost -- above all else -- to secure the safety of Japanese nationals in China", he said.

Fujimura's comments come as the Japanese consulate in Shanghai reported a series of physical attacks.