Defense Minister Itsunori Onodera and his Vietnamese counterpart, Phung Quang Thanh, have agreed to boost cooperation in maritime security amid concern over China's growing naval activities, Japanese officials said.

During talks Monday in Hanoi, Onodera was quoted by the officials as telling Thanh that the rule of law and dialogue are vital in settling security disputes.

With Japan embroiled in the Senkaku Islands row with China, Tokyo has been keen to strengthen ties with nations such as Vietnam that are involved in territorial disputes of their own with Beijing.

Onodera, in Vietnam as part of a five-day trip that will also take him to Thailand, met Thanh most recently late last month on the sidelines of a defense ministers' meeting of the Association of Southeast Asian Nations and their dialogue partners in Brunei.

China claims virtually the entire South China Sea, but Vietnam and other Southeast Asian countries also claim some areas.