The exchange with the South American nation suggests the U.S. president also sees trade as a tool to influence other policies of foreign countries.

CNBC's Megan Cassella reports on the latest tariff news from the White House. Mary Trump issues warning on long-term impact of Donald Trump move Rotten Tomatoes Names Greatest Movie of the 21st Century

President Donald Trump welcomed leaders of five African nations, hailing the continent’s economic potential as his administration seeks to expand US access to critical minerals and other natural resources.

The U.S. said it would levy a 20% tariff for exports from Vietnam, and a 40% tariff on transshipped goods. How that’s defined is critical for the administration’s trade deals.

President Donald Trump met the presidents of five African nations -- Senegal, Liberia, Guinea-Bissau, Mauritania and Gabon -- in what the White House describes as a push to deepen trade, including precious medals.

The majority of the new tariffs announced closely reflect the rates proposed in April; Laos and Burma are set to face the highest levy at 40%. Meanwhile, goods from Cambodia and Thailand will face slightly lower rates of 36%. Additionally, Brunei, Japan, Kazakhstan, Malaysia, Moldova, South Korea and Tunisia will see a 25% tariff hike.

Major stock indexes were little changed on Tuesday as investors digested the latest news in U.S. President Donald Trump's tariff rollout, and the yen extended its slide against the dollar on planned 25% duties on goods from Japan.

U.S. trade policy isn't supposed to follow the whims of an erratic and ignorant president who can't make up his mind