President Donald Trump signed a memo Thursday directing his administration to start determining what level of reciprocal tariffs the U.S. will impose on foreign imports—after long promising to announce the new round of tariffs—but the new taxes will not take effect yet.

The president tasked top Cabinet officials to study the matter further before deciding on specifics, a process the White House said could take weeks or months.

Trump calls it unfair that some countries apply higher tariffs to specific American goods than the U.S. applies back. A new executive order seeks to change that.