The Association of Southeast Asian Nations and its six regional partners, including Japan, China and India, declared Tuesday the start of negotiations for a free-trade agreement that could create a huge integrated market compromising more than 3 billion people.

The move toward creating the Regional Comprehensive Economic Partnership comes as the United States is seeking to create another vast free-trade bloc through the Trans-Pacific Partnership initiative.

If the RCEP and TPP, which is currently being negotiated by 11 countries, are created, each could be similar in economic size to the European Union. The 16 countries involved in the RCEP negotiations have a combined nominal gross domestic product of about $19 trillion, or about 30 percent of the world's GDP.