Developing nations in South-east Asia, including war-torn and earthquake-hit Myanmar, and several African nations are among the trading partners facing the highest tariffs set by US President Donald Trump’s sweeping tariffs.

Upending decades of US trade policy and threatening to unleash a global trade war, Trump on Wednesday announced a raft of tariffs he said were designed to stop the US economy from being “cheated”.

“This is one of the most important days, in my opinion, in American history,” said Trump on Wednesday. “It’s our declaration of economic independence.”

The US president hailed the moment as “liberation day”, but the tariffs are likely to be met with loud protest in some of the world’s weakest economies. One expert said Trump was likely to be targeting countries that receive investment from China, regardless of the situation in that country.

The tariffs comes as many countries in South-east Asia are already grappling with the fallout from the cuts to USAid, which provides humanitarian assistance to a region vulnerable to natural disasters and support for pro-democracy activists battling repressive regimes.

Cambodia, a developing economy where 17.8% of the population live below the poverty line according to the Asian Development Bank (ADB), is the worst-hit country in the region with a tariff rate of 49%.

In second place is the landlocked South-east Asian nation of Laos, a country heavily bombed by the US during the cold war, with 48%. According to the ADB, Laos has a poverty rate of 18.3%.

Not far behind is Vietnam with 46% and Myanmar, a nation reeling from a devastating earthquake on Friday, and years of civil war following a 2021 military coup, with 44%.

Indonesia, the biggest economy in South-east Asia, faces with a 32% tariff rate, while Thailand, the second-largest, has been hit with a rate of 36%.

Major US rival and trading partner China has been hit with a 34% reciprocal tariff, on top of the 20% levy already imposed.

Dr Siwage Dharma Negara, a senior fellow at the ISEAS-Yusof Ishak Institute in Singapore, said the the tariffs on South-east Asia nations were really intended to hurt China.

“The administration thinks is that by targeting these countries they can target Chinese investment in countries like Cambodia, Laos, Myanmar, Indonesia. By targeting their products maybe it will effect Chinese exports and the economy,” he said.

“The real target is China but the real impact on those countries will be quite significant because this investment creates jobs and export revenue.”

Tariffs on countries like Indonesia, he said, would be counterproductive for US, and the detail of how they would be applied remained unclear.

“Some garments and footwear [companies], some are American brands like Nike, or Adidas, US companies that have factories in Indonesia. Will they face the same tariffs as well?” he said.

Other nations among the hardest hit are several nations in Africa, including Lesotho –a country that Trump said last month “nobody has ever heard of” with 50%, Madagascar with 47% and Botswana with 37%. Lesotho, a small mountainous kingdom surrounded by South Africa, has the second-highest level of HIV infection of the world, with almost one in four adults HIV-positive.

In South Asia, Sri Lanka is facing a 44% tariff. In Europe, Serbia faces a 37% rate.

In addition to the reciprocal tariffs on a few dozen countries, Trump will impose a 10% universal tariff on all imported goods. That tariff will go into effect on 5 April, while the reciprocal tariffs will begin on 9 April.

The US president has justified the changes saying they are retribution for countries that have long “cheated” America, and the levies will bring jobs back to the US.

But economists have warned the sweeping changes will raise costs, threaten jobs, slow growth and isolate the US from a system of global trade it pioneered, and furthered over several decades.

“This is how you sabotage the world’s economic engine while claiming to supercharge it,” said Nigel Green, CEO of global financial advisory deVere Group.

“The reality is stark: these tariffs will push prices higher on thousands of everyday goods – from phones to food – and that will fuel inflation at a time when it is already uncomfortably persistent.”