A Vietnamese protester holds a banner in a rally against Beijing's deployment of an oil rig in the contested waters of the South China Sea, outside the Chinese Embassy on Sunday. Pic: AP.

HANOI, Vietnam (AP) — State media say a Vietnamese patrol boat has exchanged water cannon fire with Chinese vessels near an oil rig recently positioned by China in disputed waters.

Two journalists for the Tuoi Tre newspaper reported they witnessed the exchange Monday in the South China Sea.

It was the first reported incident since last Wednesday in a tense standoff at the oil rig, which is surrounded by dozens of Chinese vessels. Both sides have accused the other of ramming ships.

The newspaper said the Vietnamese vessel displayed a banner in Chinese urging Beijing to withdraw the rig.

It said Chinese ships fired water cannons first, after which the Vietnamese ship responded.

Beijing deployed the rig on May 1, triggering the most serious incident in years in waters considered a possible global flashpoint.

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