Ministers from 16 Asia-Pacific countries said Sunday they will seek a broad agreement on their free trade talks by the end of the year as they formed a united front against the protectionist policies of U.S. President Donald Trump.

The members including Japan, China and the Association of Southeast Asian Nations apparently saw a growing need to step up efforts to bridge gaps and aim for "a package of year-end outcomes" as they pointed to "serious risks" from trade restrictive steps.

"The ministers recognized the importance of swiftly and successfully concluding RCEP negotiations," the countries discussing the Regional Comprehensive Economic Partnership said in a statement issued after their meeting in Tokyo.

The trade chiefs reaffirmed their resolve "in view of the current global trade environment which faces serious risks from unilateral trade actions and reactions, as well as their debilitating implications on the multilateral trading system," the statement said.

The negotiators have been seeking to narrow down contentious points and bridge differences in areas such as tariff reductions, intellectual property protection and cross-border e-commerce.

Speaking at a joint press conference, Singapore's Trade and Industry Minister Chan Chun Sing said the participating countries hope to see a "substantive conclusion" by the end of the year.

"We hope that with the successful conclusion of RCEP we will send a strong and powerful signal to the world that the countries involved continue to believe in free and open trade," Chan said.

Japan and Singapore co-chaired the ministerial meeting in Tokyo, the first to be held outside ASEAN countries.

Japan's Economy, Trade, and Industry Minister Hiroshige Seko said wide gaps exist over some points among the negotiating countries. Tokyo will continue to seek a high quality agreement but is ready to show "flexibility" in negotiations, the minister added.

The 16 countries, accounting for roughly a third of global economic output and trade flows, have been seeking to show progress toward a trade liberalization deal at a time when the United States is taking unilateral actions such as steep tariffs on steel and aluminum imports, fueling concerns about a global trade war.

"Amid growing concerns about protectionism, RCEP negotiations are gathering more global attention than ever in terms of whether Asia can unite and hold up the banner of free trade," Japanese Prime Minister Shinzo Abe said at the outset of the meeting.

Abe called for creating a free, rules-based and fair market, adding, "It depends on our will and action."

RCEP negotiations began in 2013, with the countries having agreed on only two out of 18 categories so far.

Some countries including Japan are pushing for a high degree of liberalization, while China and India are apparently cautious.

Last week, Tokyo almost completed its domestic procedures for the Trans-Pacific Partnership, a different free trade accord in the region that has yet to come into force following the pullout of the United States in 2017.

RCEP is larger and more diverse than the 11-member TPP, which now makes up some 13 percent of the world's gross domestic product.

The 16 negotiating countries are the 10 ASEAN members -- Brunei, Cambodia, Indonesia, Laos, Malaysia, Myanmar, the Philippines, Singapore, Thailand and Vietnam -- plus Japan, China, India, South Korea, Australia and New Zealand.