President Truong Tan Sang made the comments in Japan's parliament during a four-day visit.

"Vietnam has always maintained these principles over maritime disputes - resolution by peaceful means, compliance with international law, and respect for each other's due rights and sovereignty," the Vietnamese leader said.

"Countries concerned should not make the situation complex, but rather exercise self-restraint. They should neither use force nor threaten to use force."

Sang did not make a direct reference to any particular country.

But Vietnam and three other members of the Association of the Southeast Asian Nations (ASEAN) - the Philippines, Malaysia and Brunei - have opposed Beijing's attempt to claim almost all of the South China Sea.

Sang said he hoped to strengthen ties with Japan, which is also embroiled in a separate and bitter territorial dispute with China.

Tokyo has called for stronger security ties with ASEAN members to try to ease the growing territorial tensions.

"We deeply believe that relations between the two countries will be strengthened and expanded every day ... which will make a significant contribution to securing peace, stability and cooperation in the Asia-Pacific region," Sang said.

At a joint press briefing Tuesday evening, Sang and Japanese Prime Minister Shinzo Abe said they discussed regional peace, loans and grant aid to Vietnam as well as the possibility of Japan sending patrol boats to the country.

"The two countries' cooperation in maintaining order in the sea and air is extremely important for regional peace and stability," Abe told reporters.

Japan and China are locked in a bitter row over islands in the East China Sea administered by Japan as the Senkakus, but claimed by China as the Diaoyu Islands.

Chinese government ships and planes have been seen off the disputed islands numerous times since Japan nationalised some of the archipelago in September 2012, sometimes within Japan's territorial zone.

The dispute with Tokyo - which has sparked air and sea confrontations - has exacerbated animosity over Japan's military incursions across East Asia in the first half of the 20th century.

Agence France Presse - March 19, 2014