Beijing has increased tension in a disputed part of the South China Sea by sending a patrol ship to protect fishing boats after the United States deployed a destroyer in the area. The American move was in response to alleged Chinese harassment of one of its surveillance vessels.

The Yuzheng 311, a converted naval rescue vessel, is the largest and most modern patrol ship in the Chinese Navy, the Beijing News said. It was due to arrive in the Paracel Islands yesterday to patrol China’s exclusive economic zone and to "strengthen fishery administration" in the South China Sea. It will patrol the waters around the Paracels and the Spratly Islands, protecting Chinese fishing boats and transport vessels.

The remote reefs and atolls that comprise the Spratly islands are claimed by China, Vietnam, Malaysia, the Philippines, Brunei and Taiwan. The islands lie on major shipping routes for oil tankers travelling between the Middle East and Japan, South Korea and China. They may also be above undersea oil reserves.

Beijing was enraged by a law passed last week by the Philippines laying claim to the disputed islands, describing the action as illegal.

The timing of the deployment of the patrol vessel appeared to be a response to a build-up of American might in the region. The United States dispatched a destroyer armed with torpedoes and missiles to escort its surveillance ships after harassment earlier this month by the Chinese Navy.

Five Chinese ships engaged in what the Pentagon described as aggressive and co-ordinated manoeuvres around the unarmed surveillance ship Impeccable, forcing it to respond by dousing the Chinese ships with fire hoses.

Chinese naval officers said that the US ship was on a spying mission. It said it had made repeated representations to the US to stop sailing so close to Chinese waters and within its exclusive economic zone. Washington says that the confrontation took place in international waters, but Beijing claims nearly all of the South China Sea as its own.

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