Time is running out for countries and regions hoping to negotiate a break from what US President Donald Trump calls "reciprocal tariffs." His press secretary said he is carrying through on placing additional levies on Chinese exports, bringing the total 104 percent. The tariffs will go into effect just after midnight on Wednesday eastern time in the US.

White House Press Secretary Karoline Leavitt explained the move on Tuesday in Washington. She said: "It was a mistake for China to retaliate. The president, when America is punched, he punches back harder."

After taking office, Trump increased tariffs on Chinese imports by 20 percent. Then, last week, he announced a sweeping new round of levies worldwide, with an additional 34 percent tariff on China.

Leaders in Beijing retaliated by announcing their own 34-percent levies on US imports. Trump responded by threatening, and carrying through on, additional tariffs of 50 percent.

A spokesperson for China's commerce ministry issued a statement calling the threat "a mistake on top of a mistake." It said that "China will fight to the end."

Trump took to social media on Tuesday to say his administration is "waiting for their call," suggesting an openness to dialogue.

Leavitt said officials from nearly 70 countries have reached out for negotiations.