The container ship, the Touska, was sanctioned by the U.S. Treasury over links to Iranian weapons programs.
The vice president is again center stage, after abruptly leaving the first round of high-level Iranian peace talks without an agreement.
Maritime and military law experts say an expansion of the naval blockade announced last week raises legal and practical questions but has ample historical precedent.
The leader of the Iran-backed militia said that a more durable cease-fire with Israel would require the fulfillment of a list of longstanding demands.
Analysts said energy and shipping companies would be reluctant to fully restore operations until they were confident that hostilities were over.
On a day when both Iran and the United States declared the Strait of Hormuz opened, hopes for an agreement rose. But statements from President Trump and Iranian leaders about negotiations were sometimes at odds.
But analysts said it was not clear how quickly the oil industry in the Persian Gulf would be able to get back to normal.
Our business reporter Peter Eavis breaks down how American military ships have blocked Iranian-linked vessels from using the Strait of Hormuz as the U.S. encourages other vessels to make the passage.
If tankers do not soon begin crossing the Strait of Hormuz, airlines in Europe may not have enough jet fuel to operate all of their flights.
The comments come as peace talks between Iran and the United States have not yet resumed and a cease-fire is set to expire next week.