BEIJING -- Unilateralism and protectionism are an act of self-isolation and inconsistent with the law of the market and international rules, a Foreign Ministry spokesperson said on Friday.

Foreign Ministry spokesperson Hua Chunying made the remarks when commenting on an open letter by more than 1,100 US economists on Thursday warning President Donald Trump and US Congress not to repeat the mistakes made in the 1930s by adopting trade protectionism policies.

The economists sent a letter to Trump and the Congress to urge them to step back from tariff threats, arguing that similar action taken by the Congress in the 1930s sank the US economy into the Great Depression.

The economists said protective duties would operate to increase the prices which US domestic consumers would have to pay, and high tariffs measures would impact US relations with other countries and is not conducive to the world peace.

"We have all noted that in recent days, all parties in the international community have frequently called on the United States to respect the WTO and abide by multilateral rules. There are also more and more people in the United States openly opposing the use of trade protectionism by the US side," said Hua.

She said that the letter pointed out the essence of and hazards that would be brought about by the move the US side took to impose additional tariffs, as well as the potential for self-harm.