Iran's ambassador to Britain warned against escalating tensions on Sunday, a day ahead of an expected response from the UK which could include fresh sanctions on Tehran or other steps after its seizure of a British-flagged oil tanker.
Britain has called the capture of the Stena Impero in the Strait of Hormuz on Friday a "hostile act".
Below are details about the Strait:
WHAT IS THE STRAIT OF HORMUZ?
* The strait lies between Oman and Iran
* It links the Gulf with the Gulf of Oman to the south andthe Arabian Sea beyond * It is 21 miles (33 km) wide at its narrowest point, withthe shipping lane just two miles (3 km) wide in either direction
* The UAE and Saudi Arabia have sought to find other routes to bypass the Strait, including building pipelines
WHY DOES IT MATTER?
* Almost a fifth of the world's oil passes through theStrait - some 17.4 million barrels per day (bpd) versusconsumption of about 100 million bpd in 2018, data fromanalytics firm Vortexa showed
* OPEC members Saudi Arabia, Iran, the UAE, Kuwait and Iraqexport most of their crude via the Strait
* Qatar, the world's biggest liquefied natural gas (LNG)exporter, sends almost all of its LNG through theStraitPOLITICAL TENSIONS
* The United States has imposed sanctions on Iran aimed athalting its oil exports
* U.S. waivers which had allowed continued sales of Iranianoil to eight countries - China, Greece, India, Italy, Japan,South Korea, Taiwan and Turkey - expired on May 2
* Iran has threatened to disrupt oil shipments through theStrait of Hormuz if the United States tries to strangle itseconomy
* The U.S. Fifth Fleet, based in Bahrain, is tasked withprotecting commercial shipping in the regionMAJOR PAST INCIDENTS
* 1980-1988 - During the Iran-Iraq war, the two sides seekto disrupt each other's oil exports in what is known as theTanker War
* July 1988 - U.S. warship Vincennes shoots down an Iranianairliner, killing all 290 aboard, in what Washington says was anaccident and Tehran says is a deliberate attack * Early 2008 - The United States says Iranian vesselsthreaten three U.S. Navy ships in the Strait
* July 2010 - Japanese oil tanker M Star is attacked in theStrait - a group called Abdullah Azzam Brigades linked to alQaeda claims responsibility * January 2012 - Iran threatens to block the Strait inretaliation for U.S. and European sanctions aimed at curbingTehran's nuclear programme
* May 2015 - Iranian ships seize a container ship in theStrait and fire shots at a Singapore-flagged tanker which Iransays damaged an oil platform
* July 2018 - President Hassan Rouhani hints Iran coulddisrupt oil trade through the Strait in response to U.S. callsto reduce Iran's oil exports to zero
* May 2019 - Four ships, including two Saudi oil tankers,are attacked in the Gulf just outside the Strait. U.S. officialsblame Iran, Tehran denies the charges * June 2019 - Two tankers are attacked south of the Straitwhich Washington blames on Iran and Tehran denies
* June 2019 - Iran shoots down a U.S. drone
* July 2019 - The USS Boxer destroys an Iranian drone in theStrait after it threatens the U.S. Navy ship but Iran denies ithas lost a drone
* July 2019 - Iran seizes British-operated oil tanker StenaImpero in the Strait