Vietnam on Friday asked China to remove a "U-shaped" line showing its claims to over 80 percent of the East Sea from its map on a newly launched online mapping service.

The China's State Bureau of Surveying and Mapping has critically violated Vietnam's sovereignty over the Hoang Sa and Truong Sa archipelagoes by presenting the map with the nine-dotted line on the two websites www.tianditu.cn and www.chinaonmap.cn , said spokeswoman Nguyen Phuong Nga of the Ministry of Foreign Affairs.

It has also violated Vietnam's sovereignty rights and jurisdiction in its Exclusive Economic Zone (EZZ) of 200 nautical miles, she added.

Under the United Nations Convention on Law of the Sea an island can generate its own EZZ of 200 nautical miles. A state has the right to use resources in the EEZ and regulate the behavior of other states in that area.

According to Nga, the act also violates the declaration on the Conduct of Parties in the South China Sea (DOC), which China and ASEAN member states signed in 2002.

Vietnam objects to this act and demands that China promptly removes violating data from the websites, she stressed.

China needs to follow the shared awareness of the two countries' high-ranking leaders about maintaining peace and stability; and not complicate or extend disputes in the East Sea, the spokeswoman said.