Defense Secretary Pete Hegseth said Tuesday morning at a Pentagon briefing that the U.S.-Iran ceasefire "is not over," amid the sides exchanging fire at or near the Strait of Hormuz.

Hegseth also said the U.S. guiding vessels through the strait, a global shipping channel off the Iranian coast, is a "temporary solution," according to CBS News. 

"Iran cannot be allowed to block innocent countries and their goods from an international waterway," he said.

Iranian vessels on Monday fired on U.S. ships guiding vessels through the strait, resulting in the U.S. sinking several small Iranian boats, CBS also reports.

Hegseth also said the U.S. effort to guide commercial vessels in the strait, known as "Project Freedom," is "separate and distinct from Operation Epic Fury, which is the U.S. war on Iran that began Feb. 28 with air strikes.