The foreign ministry in Hanoi said the collisions took place on Sunday and caused considerable damage to the Vietnamese ships. Six people sustained minor injuries, it said.
"On May 4, Chinese ships intentionally rammed two Vietnamese Sea Guard vessels," said Tran Duy Hai, a foreign ministry official and deputy head of Vietnam's national border committee.
"Chinese ships, with air support, sought to intimidate Vietnamese vessels. Water cannon was used," he told a news conference in Hanoi. Six other ships were also hit, other officials said, but not as badly.
Dozens of navy and coastguard vessels from both countries are in the area where China has deployed the giant rig, Vietnamese officials have said.
More - http://www.reuters.com/article/2014/05/0...3C20140507