FACTBOX: The Strait of Hormuz, Iran and the risk to oil

(Reuters) - Iran said on Tuesday it will not rule out using oil as a weapon if the United States resorts to military action against the Islamic republic over its nuclear program.

Iran's OPEC governor, Hossein Kazempour Ardebili, told Iran's Sharq newspaper it could use oil as a "tool" and stop its exports to world markets that would result in an oil shock.

Analysts also fear Iran, OPEC's second largest exporter, could seek to impede traffic through the Strait of Hormuz in any retaliation by threatening merchant shipping. U.S. naval chiefs are concerned that Iran could resort to mining the strait and the wider Gulf in a major conflict.

The strategic sea channel which shares Iran's coastline at the entrance to the Gulf is the world's most important waterway or choke point because of the huge volume of oil exported through it daily.

-- Oil flows through the Strait account for roughly 40 percent of all globally traded oil supply, according to the U.S. Energy Information Administration (EIA). The figure fluctuates with changing OPEC output.

-- In May, the International Energy Agency (IEA) estimated 13.4 million barrels per day (bpd) of crude passing through the narrow channel on tankers, down from 16-17 million barrels before a round of OPEC production cuts.

-- An additional 2 million barrels of oil products, including fuel oil, are exported through the passage daily as well as liquefied natural gas.

-- Exports from the world's largest liquefied natural gas exporter Qatar also pass through the Strait en route to Asia and Europe. 31 million tons a year.

-- Ninety percent of oil exported from Gulf producers is carried on oil tankers through the Strait.