French President Emmanuel Macron said on Thursday it would be unrealistic to launch a military operation to force open the Strait of Hormuz, after President Donald Trump challenged U.S. allies to work towards reopening it.

Thousands of people have been killed across the Middle East since Feb. 28, when the U.S. and Israel struck Iran, triggering Iranian attacks on Israel, U.S. bases, and the Gulf states, and Tehran effectively closing the waterway that carries about a fifth of global oil and liquefied natural gas supplies.

"Some people defend the idea of freeing the Strait of Hormuz by force via a military operation, a position sometimes expressed by the United States, although it has varied," Macron told reporters during a trip to South Korea.

"This was never the option we have supported because it is unrealistic," he said. "It would take forever, and would expose all those who go through the Strait to risks from the guardians of the revolution but also ballistic missiles," he said.

Macron, who has worked with European and other allies to build a coalition to guarantee free passage through Hormuz once hostilities have stopped, said this could only be done by talking to Iran.

"What we say from the beginning is that this strait must be reopened because it is strategic for energy flows, fertilizers and international trade, but that it can only be done in consultation with Iran," he said.

Asked about Trump's criticism of NATO allies and threats to pull the U.S. out of the alliance, Macron said:

"I don't want to provide a running commentary of an operation the Americans have decided on their own with Israel. They can deplore the fact they're not being helped, but that's not our operation. We want peace as soon as possible."

Macron also said that Trump's comments mocking him and his wife Brigitte were "neither elegant, nor commensurate" with the moment.