BEIJING  - Beijing said it would protest to Japan after the arrest of a group of pro-China activists who landed on a disputed island on Wednesday, while state media blasted Tokyo for escalating tensions.

Japanese police held nine more people late Wednesday after authorities earlier arrested five activists on the disputed archipelago known as Diaoyu in China and Senkaku in Japan.

“China’s foreign ministry is now urgently contacting the Japanese side to lodge representations over this matter,” the official Xinhua news agency said.

In a separate report, Xinhua said the ministry would “lodge a complaint” with Japan but gave no further details of what action Beijing might undertake.

The pro-China activists from Hong Kong and Macau set sail to the disputed islands on a Chinese-flagged fishing boat from Hong Kong on Sunday.

The activists, who belong to the Action Committee for Defending the Diaoyu Islands, had said the move was aimed at countering a plan by a group of Japanese lawmakers to visit the disputed islands this weekend.

A separate commentary published by Xinhua late Wednesday said the dispute had raised tensions over territory to a new high and said the activists were “flagrantly arrested” while trying to set foot on Chinese territory.