US President Donald Trump said Thursday he would impose an additional 10 percent tariff on Chinese imports while moving ahead with levies on Canada and Mexico next week, citing "unacceptable" drug smuggling.

Markets opening in Asia on Friday tracked losses across the world from the previous day, as the Republican's latest comments fanned fears of a global trade war.

Trump had announced -- then halted -- sweeping 25 percent levies on Canadian and Mexican imports this month over illegal immigration and deadly fentanyl, with Canadian energy to face a lower rate.

But the month-long pause ends Tuesday.

Following reporters' questions on whether he planned to proceed on the tariffs next week, Trump wrote on social media Thursday that until the problem of fentanyl stops "or is seriously limited," the proposed levies will happen as scheduled.

"China will likewise be charged an additional 10 percent Tariff on that date," he added, referring to March 4.

Earlier this month, Trump imposed a sweeping 10 percent tariff hike on imports from China, prompting Beijing to retaliate.

A US official confirmed to AFP that the new 10 percent levy adds to the existing one over fentanyl, saying that there has been "insufficient progress" on the drug front.

The official added that Washington had to act against all three countries in order to tackle the fentanyl issue.

On Thursday, Chinese Commerce Minister Wang Wentao expressed concerns over Washington's earlier 10 percent tariff.

"China firmly opposes this and has taken corresponding countermeasures," Wang said in a letter to newly confirmed US Trade Representative (USTR) Jamieson Greer.

China's leadership will convene next week to hammer out plans to shield its economy from Trump's threats.

Mexican President Claudia Sheinbaum on Thursday said she hoped to speak with Trump to avoid being hit by his threatened tariffs.

A high-level Mexican delegation is in Washington in search of an agreement.

And Canadian Prime Minister Justin Trudeau said officials are working around the clock to avert US levies but would have an "immediate" response if measures were imposed next week.

Trudeau has repeatedly stressed that less than one percent of the fentanyl and undocumented migrants that enter the United States come through the Canadian border.

Trump's threats have sent shivers through major exporter countries.

Asian markets were all well in the red early Friday, with Tokyo briefly shedding three percent.

Reciprocal tariffs

Besides levies over fentanyl, Trump added on Truth Social that an April 2 date for so-called reciprocal tariffs "will remain in full force and effect."

These will be tailored to each US trading partner, with details to come after government agencies complete studies that Trump has called for on trade issues.

In his letter to Greer, Wang noted that Trump has called for many trade investigations "aimed at China" and urged both sides to resolve their differences via dialogue.

Beijing has pushed back against US fentanyl concerns, saying Washington has to solve the issue itself rather than taking aim at other countries with levies.

Rather than the drugs being supplied directly to the United States, a Congressional Research Service report noted last year that US-bound fentanyl appears to be made in Mexico using chemical precursors from China.

While some precursors face international controls, others may be made and exported legally from countries like China.

In early February, China's foreign ministry warned that fresh tariffs could hurt counternarcotics cooperation.

AFP