The US president stopped short of issuing new threats, but called Thursday's drone attack "foolish."

Iran launched explosive-laden suicide drones at a cargo ship transiting the Strait of Hormuz on Thursday.

A ceasefire between the U.S. and Iran went into effect earlier this month and called for an immediate end to military operations from both countries and their allies.

The free flow of commerce was one of the 14 points of understanding that the U.S. and the Iran reached.