WASHINGTON: US tariffs will kick in on Aug 1 if trading partners from Taiwan to the European Union do not strike deals with Washington, Treasury Secretary Scott Bessent said on Sunday (Jul 6).

The rates will "boomerang back" to the sometimes very high levels which President Donald Trump had announced on Apr 2 - before he suspended the levies to allow for trade talks and set a Jul 9 deadline for agreement, Bessent told CNN.

Bessent confirmed comments by Trump to reporters aboard Air Force One on Friday in which he also cited a new deadline: "Well, I'll probably start them on Aug 1. Well, that's pretty early. Right?"

The president said he had signed 12 letters to be sent out, likely on Monday.

The tariffs were part of a broader announcement in April where Trump imposed a 10 per cent duty on goods from almost all trading partners, with a plan to step up these rates for a select group within days.

But he swiftly paused the hikes until Jul 9, allowing for trade talks to take place.

Countries have been pushing to strike deals that would help them avoid these elevated duties.

So far, the Trump administration has unveiled deals with the United Kingdom and Vietnam, while Washington and Beijing agreed to temporarily lower staggeringly high levies on each other's products.

As his Jul 9 deadline approaches, Trump has repeatedly said he plans to inform countries of US tariff rates by sending them letters.

Aboard Air Force One on Friday, Trump said sending notices would be much easier than "sitting down and working 15 different things ... this is what you have to pay, if you want to do business (with) the United States."

Bessent pushed back at CNN host Dana Bash's assertion the administration was using threats rather than negotiations, and denied that Trump was setting a new deadline with the August 1 date.

"It's not a new deadline. We are saying, this is when it's happening, if you want to speed things up hav...