Ministers from Japan, China and South Korea will formally declare Tuesday the start of negotiations to conclude a trilateral free-trade agreement on the sidelines of the East Asia Summit in Cambodia, sources said Friday.

The announcement paves the way to creating a major trade bloc among the three Asian neighbors that together account for about 20 percent of global gross domestic product.

Seeing the benefits of a trilateral FTA, Tokyo, Beijing and Seoul plan to set aside obstacles such as the territorial dispute between Tokyo and Beijing in moving forward the negotiations and instead push for stronger economic ties, the sources said.

Japan will be represented by trade minister Yukio Edano.

Top leaders of the three countries agreed in May during talks in Beijing to formally start talks by the end of the year on signing a three-way FTA.

Working-level consultations toward starting the FTA negotiations ensued despite heightened tensions between Japan and China over the Japanese-controlled Senkaku Islands in the East China Sea, after Tokyo effectively nationalized the islets in September. Beijing claims the uninhabited islets, which Japan first put under its control in 1895, and calls them Diaoyu.

Japan also has a dispute over the Takeshima islets, which are held by South Korea and referred to on the peninsula as Dokdo.

Parallel to the trilateral FTA, leaders from the 10-member Association of Southeast Asian Nations and its six regional partners, including Japan, China and South Korea, are expected to announce the launch of negotiations for a regionwide FTA.