President Donald Trump sent letters to the leaders of five more countries Wednesday, adding to the growing list of US trading partners for whom he has set new tariff rates.

WASHINGTON (Reuters) -U.S. President Donald Trump on Wednesday issued a round of tariff letters to six countries, including Algeria, Brunei, Iraq, Libya, Moldova and the Philippines. The letters call for tariffs of 30% on Algeria, 25% on Brunei, 30% on Iraq, 30% on Libya, 25% on Moldova and 25% on the Philippines.

Trump uses tariffs as a key tool to force changes to U.S. trade relationships, but his on-again-off-again approach has roiled markets and stoked uncertainty.