WATCH: Several hurt as China rams vessels in disputed sea

MANILA, Philippines — In a video released by Vietnam's Ministry of Defense on Wednesday, Chinese ships backed by helicopters are seen ramming Vietnamese vessels trying to prevent China from putting up an oil rig in disputed waters of South China Sea near the Paracel Islands.

Ngo Ngoc Thu, vice commander of the High Command of Vietnam Marine Police, said the footage was provided by Vietnamese fisheries surveillance force showing one of the two incidents this week when Chinese maritime authorities rammed, hit or used water cannons to deter several Vietnamese vessels.

The video was posted on YouTube as taped from a press conference led by Thu, whose comments are subtitled on the video.

"It can be clearly seen that the cannons on the Chinese ship was uncovered and ready for using at any time," Thu remarked.

Windows of the Vietnamese vessels were also smashed, injuring Vietnamese crew members.

Thu said that China Marine Police still hit a Vietnamese vessel after it turned around and sped up to avoid a confrontation.

Also read: China begins drilling for oil in disputed Sea; Vietnam protests