HANOI (Reuters) -China's President Xi Jinping on Monday called for stronger ties with Vietnam on trade and supply chains amid disruptions caused by U.S. tariffs, as he attended in Hanoi the signing of dozens of cooperation agreements between the two Communist-run nations.

The visit, planned for weeks and part of a wider trip in Southeast Asia, comes as Beijing faces 145% U.S. duties, while Vietnam is negotiating a reduction of threatened U.S. tariffs of 46% that would otherwise apply in July after a global moratorium expires.

"The two sides should strengthen cooperation in production and supply chains," Xi said in an article in Nhandan, the newspaper of Vietnam's Communist Party, posted ahead of his arrival on Monday. He also urged more trade and stronger ties with Hanoi on artificial intelligence and the green economy.

"There are no winners in trade wars and tariff wars," Xi added, without mentioning the U.S. specifically.