President Donald Trump said his 50% tariff on copper imports will take effect on Aug. 1, noting he made the decision after a national security assessment.

President Donald Trump said the US would begin levying a 50% tariff on copper imports from Aug. 1, confirming a move that will hurt American producers of everything from automobiles to appliances.The higher-than-expected levy was signaled by Trump in comments to reporters on Tuesday,

The president was following through on an earlier statement that he would target a key metal used for semiconductors, lithium-ion batteries and more.

U.S. President Donald Trump announced on Wednesday a new 50% tariff on copper to start on August 1 in a bid to promote domestic development of an industry critical to defense, electronics and automobiles.

Copper futures rose dramatically following President Trump's plan for a 50% import tariff, pushing domestic prices to a 25% premium over global markets amid growing demand.

Trump also said he would soon announce tariffs “at a very, very high rate, like 200%,” on pharmaceutical imports.

CNBC's Steve Sedgewick, Karen Tso and Julianna Tatelbaum discuss the copper market after U.S. President Donald Trump says he will impose a 50% tariff on imports, sending U.S. prices of the metal jumping.

President Donald Trump said Tuesday he’s imposing a new 50% tariff on all copper. However, it’s unclear when the new tariff would take effect.

None of the countries targeted in the first batch of letters — the Philippines, Brunei, Moldova, Algeria, Libya, Iraq and Sri Lanka — is a major industrial rival to the United States.