Tokyo: China`s coastguard approached disputed islands in the East China Sea for the first time on Wednesday and a Chinese military plane made an unprecedented journey between Okinawan islands, Japanese officials said.
The moves sparked alarm in Tokyo, where the government said it was a sign of "China`s ever-growing maritime advance".
Four ships, bearing the legend "China Coast Guard", were spotted in the contiguous waters of the Senkaku islands, which Beijing claims as the Diaoyus, Japan`s coastguard said.
Contiguous waters are a 12-nautical-mile band that extends beyond territorial waters. Under international rules, they are not the preserve of any one country, although the resident power has certain limited rights.
Meanwhile, a Chinese Y-8 early warning plane was seen flying over international waters between the Okinawan main island and another Japanese island of Miyako, the defence ministry said in a press release.
Japanese fighter planes were scrambled to keep a watch on the Chinese aircraft, the statement said.
Japanese Defence Minister Itsunori Onodera told reporters it was the first time a Chinese military plane had flown through the area on its way to the Pacific.
"We see it as a sign of China`s ever-growing maritime advance," he said.
Vessels from China`s Maritime Surveillance have frequently plied waters around the Senkaku islands -- including territorial waters -- since a huge row over their ownership flared last year when Tokyo nationalised three of them.
Confrontations between Japan`s coastguard and these ships have customarily been limited to an exchange of warnings, with each side telling the other to leave.
But this is the first time Beijing`s coastguard has been seen in the area.
Chinese media reported this week that a unified coastguard agency has gone into operation, integrating marine surveillance, the existing coastguard -- which came under the police -- fisheries law enforcement and Customs` anti-smuggling maritime police.
Chinese academics were reported as saying that the move would mean more armed ships.