(CNN) -- The U.S. Navy said Iran's threat to block the strategically and economically important Strait of Hormuz is unacceptable.
"The free flow of goods and services through the Strait of Hormuz is vital to regional and global prosperity," Navy 5th Fleet in Bahrain spokeswoman Cmdr. Amy Derrick Frost told reporters on Wednesday.
"Anyone who threatens to disrupt freedom of navigation in an international strait is clearly outside the community of nations; any disruption will not be tolerated."
The 34-mile-wide shipping channel leads in and out of the Persian Gulf between Iran and Oman. It is strategically important because tankers carrying oil travel through it.
Iran's vice president has warned that the country could block the strait if sanctions are imposed on its exports of crude oil. France, Britain and Germany have proposed sanctions to punish Iran's lack of cooperation on its nuclear program......
The 5th Fleet is based in Bahrain, and Frost noted that the Navy "maintains a robust presence in the region to deter or counter destabilizing activities."
"We conduct maritime security operations under international maritime conventions to ensure security and safety in international waters for all commercial shipping to operate freely while transiting the region," she said.
Asked whether the fleet would be able to keep the strait open if Iran moved to close it, she said, "The U.S. Navy is a flexible, multi-capable force committed to regional security and stability, always ready to counter malevolent actions to ensure freedom of navigation."
Frost was also asked whether keeping the strait open is part of the fleet's mandate.
She said it is "committed to protecting maritime freedoms that are the basis for global prosperity. This is one of the main reasons our military forces operate in the region.
"The U.S. Navy, along with our coalition and regional partners, operates under international maritime conventions to maintain a constant state of high vigilance in order to ensure the continued, safe flow of maritime traffic in waterways critical to global commerce."
The French Foreign Ministry stressed that the waterway is an international strait........
Iran is holding a 10-day military exercise in an area from the eastern part of the strait out into the Arabian Sea. Western diplomats describe the maneuvers as further evidence of Iran's volatile behavior.
In 2009, 15 million barrels passed through the strait every day [total global oil daily production is around 80 million barrels], according to the U.S. Energy Information Administration.[China, Japan and Europe are far more dependent on Persian Gulf oil than is the US. But control over this flow is an essential part of US global domination and has been so since the FDR administration]