The NATO secretary general has said he is "concerned" about a build-up of US forces in the the Gulf and warned it could lead to an accidental conflict.
"We're all of course concerned because conflict or situations that evolve in that region will have implications for all NATO allies," Jens Stoltenberg told Sky News.
"When we have military forces as we see in that region, there is always a risk for miscalculations, that is why it is important that all involved convey a very clear message to avoid this calculations."
Mr Stoltenberg met US secretary of state Mike Pompeo in Brussels on Monday.
When asked whether he was confident in the US intelligence that suggested an immediate threat to US forces, he said: "This is a US decision, this is a US deployment.
"It is not for me as secretary general of NATO to speak on behalf of the United States.
"The United States is consulting closely with NATO allies on different levels and in different ways."
In recent weeks, the US has moved an aircraft carrier and B-52 long-range bombers into the Gulf region as a show of strength.
At the weekend, four cargo ships were targeted off the UAE coast but as yet there is little evidence about who was responsible.
Mr Stoltenberg was supportive of the US, which is NATO's biggest member.
He said: "What is of concern for all NATO allies is what Iran has been doing for many, many years, trying to destabilise the region, supporting different types of terrorist organisations, and also both the missile programme and the nuclear ambitions of Iran.
"There are disagreements on the nuclear agreement within the Alliance but all agree that it is important to prevent Iran from developing nuclear weapons."