By Lin Noueihed
The exercises took place against a backdrop of high tensions between Iran and the West over Tehran's nuclear activities.
Speculation about a possible attack on Iran has risen since a report last month said Israel had practised such a strike. Iran on Tuesday vowed to strike shipping in the world's largest oil exporting region if it is attacked.
The U.S. Fifth Fleet, which is based on the Gulf Arab island of Bahrain, said "Exercise Stake Net" took place in the central and southern Gulf and was part of ongoing training aimed at protecting the region's oil infrastructure from any attack.
"This exercise is in no way related to reported tensions with Iran… Coalition exercises happen with a great deal of regularity," Lieutenant Nathan Christensen, a Fifth Fleet spokesman, told Reuters by telephone.
Fear of an escalation in the standoff between the West and Iran, the world's fourth-largest oil producer, over its disputed nuclear programme has helped push oil prices over $140 a barrel.
"Violent extremists are one of the principal threats, so small boats could be one form of attack. Suicide bombings could be another. There are people want to come in and do things and the coalition is here to ensure that they do not succeed. It is about protecting the regional economy and the world economy."
An aide to Iran's Supreme Leader Ali Khamenei was quoted as saying on Tuesday that Iran would hit Tel Aviv, U.S. shipping in the Gulf and U.S. interests around the world if it is attacked.
Israel, believed to be the Middle East's only nuclear-armed power, has vowed to prevent Iran from acquiring an atomic bomb.
The United States says it wants to resolve the dispute by diplomacy but has not ruled out military action.
Iran says its nuclear activities are only to produce energy for civilian use, not to make bombs.
Vice-Admiral Kevin Cosgriff, the commander of the U.S. Navy's Fifth Fleet, said last week the United States would not allow Iran to block the Gulf. But a number of incidents in the busy waterway have ratcheted up tensions in recent months.
In January, the United States said five small Iranian speedboats aggressively approached three U.S. Navy ships in the Strait of Hormuz and a radio message was transmitted, warning they could explode.
Iran said its boats were simply trying to identify the U.S. vessels and military experts have since said the warning may have come from an independent radio operator.
Two U.S. vessels took part in this week's exercise alongside a British warship and one from Bahrain. The British-led exercise began on July 3. (Editing by Samia Nakhoul)
