A video released by Vietnamese state television appears to show a large Chinese ship chasing and then sinking a small Vietnamese fishing boat in waters just west of the Vietnamese coast.
The incident, which happened on the 26 May, occurred very close to where the controversial Chinese oil rig, HD-981, is parked.
The rig is situated in an area of water that both Chinese and Vietnamese officials claim is theirs and has been a subject of tension between Chinese and Vietnamese vessels in the disputed waters.
The chase, filmed from a nearby Vietnamese boat, shows the larger Chinese vessel chasing down two Vietnamese fishing boats, before ramming into the side of one of them and tipping the ship over until it eventually sank.
A crew of 10 were on board and had to be rescued by other fishing boats in the area.
The report by VTV that accompanied the video said: “The latest images recorded by Vietnamese fishermen at the time when fishing ship DNa-90152 was sunk by a Chinese ship serve as irrefutable evidence of the inhumane actions of China against Vietnamese fishermen."
Despite the evidence pointing to an act of aggression by the Chinese vessel, authorities in Beijing have claimed that their ship was acting in self-defence and that it was the Vietnamese boats that had been the aggressors.
Chinese Foreign Ministry spokesman Hong Lei said: "In these seas. China's ships were in a defensive mode ... who was it who took the initiative for the clash? Who was it who created tension on the scene? This is very clear."
The video to come from VTV displays one in a long list of altercations between Chinese and Vietnamese boats, altercations that have intensified since the rig was towed into the disputed area of water earlier this year.
The Vietnamese claim that the rig is illegal and the Chinese’s decision to drill there is an encroachment on their territory.
They say that China has “up to 140” ships protecting the rig, including six military vessels and aircraft and these have damaged up to 24 Vietnamese ships since the rig first arrived.
China disputes this and says that the rig is well within their waters.
Last week, officials in Hanoi said 40 Chinese fishing boats had surrounded and sunk Vietnamese craft in the disputed area of water.
This was refuted by Chinese officials who said that the boat had capsized after harassing and colliding with a Chinese fishing boat.
In a statement released by the Philippines’ government on Thursday, they supported the Vietnamese claims saying that China was pursuing an “expansion agenda” and accused them of China of reclaiming land in another part of the South China Sea.
President Benigno Aquino: "We are again bothered that there seems to be developments in other areas within the disputed seas
“"The pictures that I saw were just ships that can be used for reclamation."