In this photo released by Vietnam Coast Guard, a Chinese ship, left, shoots water cannon at a Vietnamese vessel, right, while Chinese Coast Guard ship, center, sails alongside in the South China Sea off Vietnam's coast, Wednesday, May 7, 2014. Chinese ships are ramming and spraying water cannons at Vietnamese vessels trying to stop Beijing from setting up an oil rig in the South China Sea, according to Vietnamese officials and video evidence Wednesday, a dangerous escalation of tensions in disputed waters considered a global flashpoint. (AP Photo/Vietnam Coast Guard)

Hanoi - A Chinese boat rammed and sank a Vietnamese fishing vessel not far from where China has stationed a massive oil rig in disputed waters of the South China Sea, the head of Vietnam's coastguard said on Tuesday.

Vietnamese fishing boats operating nearby rescued the 10 fishermen on board following the incident on Monday, said coastguard commander Nguyen Quang Dam.

He said the ramming occurred 17 nautical miles from the rig, which has been deployed between the Paracel islands occupied by China and the Vietnamese coast.

“A Vietnamese boat from the central city of Da Nang was deliberately encircled by 40 fishing vessels from China before it was attacked by a Chinese ship,” Dam told Reuters by telephone.

There was no immediate comment from China on the latest incident to flare up since the rig was towed to waters that Hanoi also claims.

Scores of Vietnamese and Chinese ships continue to square off around the rig despite of series of collisions earlier this month.

Vietnamese Prime Minister Nguyen Tan Dung last week said his government was considering various “defence options” against China, including legal action, following the deployment of the rig. - Reuters