Political leaders must adhere to the principles of multilateralism despite swirls of anti-globalism and economic uncertainties, experts recommended at a forum in Tokyo ahead of next month’s Group of 20 summit in Osaka.

The Think 20, or T20, held for two days through Monday, drew more than 400 think tank experts from Japan and abroad. The group meets annually and submits policy recommendations to G20 member countries in 10 subject areas, such as the environment, global governance and infrastructure investment.

Reflecting recent developments in trade — most notably the clash between the United States and China as both countries ramp up tariffs on imported goods — multiple speakers touched on the topic, sharing their qualms that trade disputes will dampen global economic growth.

“Although trade negotiations seem to have progressed somewhat, a number of issues need to be resolved,” said Bank of Japan Gov. Haruhiko Kuroda, who was invited to speak Monday. “Due to the widening range of tariff increases, trade costs may rise, and corporate activity could be subdued due to reconsideration of production sites and global value chains.”

Kuroda appeared to hint at the ongoing U.S.-China trade tensions. U.S. President Donald Trump, who is visiting Japan as the country’s first state guest since Emperor Naruhito ascended the throne May 1, is expected to attend the G20 summit next month in Osaka, where he is expected to meet with Chinese President Xi Jinping to resolve differences.

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Trump’s preference for bilateral over multilateral trade negotiations has disquieted allies. Since he took office, Trump pulled the U.S. out of the Trans-Pacific Partnership framework and threatened to withdraw from the World Trade Organization.

The T20 recommends putting the WTO at the center of a “rules-based trading regime,” a move intended to curb the growth of anti-globalist sentiment.

Koji Tomita, a senior Foreign Ministry official who is Japan’s lead Sherpa for the G20 gathering, said regaining public confidence in multilateralism will be one of the summit’s goals.

“In the light of growing downturn risks, it is obvious that the Osaka summit has to focus on this condition,” Tomita said. “But the challenge is that we have to do so against the (backdrop) of declining public confidence in multilateralism.”

Kenichiro Sasae, president of the Japan Institute of International Affairs and a former Japanese ambassador to the U.S., warned of the unraveling of international cooperation prompted by a rise of populism.

Countries are increasingly pursuing their self-interests, and divisiveness has become more visible in politics and society, Sasae said.

“In spite of an unprecedented challenge against multilateralism, multilateral approaches need to be the basis and starting point (to) tackle common global challenges such as climate change, health and trade,” he said.