HANOI (REUTERS) - Vietnam on Wednesday (Aug 26) accused China of violating its sovereignty by conducting military drills in a disputed part of the South China Sea and said Beijing's actions were "complicating" negotiations on establishing a code of conduct in the region.

China this week began six days of exercises in waters near the Paracel Islands, where Vietnam has competing claims, according to the Maritime Safety Administration of Hainan, an island off China's southern coast. It was the second set of drills in the area by Beijing in two months.

"China's repeated military exercises in (the Paracel Islands) violate Vietnam's sovereignty, complicating negotiations for a Code of Conduct of Parties in the South China Sea between China and Asean," foreign ministry spokesman Le Thi Thu Hang said in a statement.

Vietnam is this year chairing the 10-member Asean regional grouping, which has had long drawn-out negotiations with Beijing over a code of conduct in the South China Sea.

China's defence ministry did not immediately respond to a request for comment.

At a June 26 summit in Hanoi, Vietnam and the Philippines - China's most vocal challengers over the sea - warned of growing regional insecurity amid concern that Beijing was advancing territorial claims under the cover of the Covid-19 pandemic.

China claims historical jurisdiction over about 80 per cent of the sea, using a U-shaped "nine-dash line" that includes swathes of Vietnam's exclusive economic zone, or EEZ, as well as the Paracel Islands and Spratly Islands. It also overlaps the EEZs of Brunei, Indonesia, Malaysia, the Philippines, Taiwan and Vietnam.

Vietnam and the Philippines last month criticised China's holding of an earlier set of military drills in the area.

The United States in June also hardened its position on the South China Sea, where it has accused China of attempting to build a "maritime empire" in the potentially energy-rich waters.