BEIJING: China's Commerce Minister Wang Wentao told the head of the World Trade Organisation that US tariffs would "inflict serious harm" on poorer nations, according to a ministry statement released on Saturday.

"These US 'reciprocal tariffs' will inflict serious harm on developing countries, especially the least developed countries, and could even trigger a humanitarian crisis," Wang told WTO chief Ngozi Okonjo-Iweala in a call on Friday, the statement said.

"The United States has continuously introduced tariff measures, bringing enormous uncertainty and instability to the world, causing chaos both internationally and domestically within the US," Wang added.

Beijing said on Friday that its 125 per cent tariffs on US goods would take effect on Saturday – almost matching the staggering 145 per cent levies imposed by Washington on Chinese goods entering the United States.