Fears six nuclear bombs 'lost' by US military could end up in enemy hands

 The vast nuclear arsenal of the US has seen some of its weaponry scattered across the globe, with atomic bombs lost to the ocean's depths - potentially waiting to be discovered by anyone.

As Donald Trump threatens to unleash "Death, Fire and Fury" on Iran, fears are mounting once more over nuclear capabilities in the Middle East.

The US has adopted the position that if it cannot locate its missing bombs, or "Broken Arrow" incidents, then neither can its adversaries.

To date, the US has a total of six unaccounted-for nuclear warheads from 32 documented Broken Arrow accidents.

Given that the detonation of even a single one of these warheads could obliterate an entire city and claim millions of lives, this appears to represent a considerable cause for alarm.

One incident in 1958 involved a fully-armed B-47 carrying a Mark 15 hydrogen bomb near Tybee Island, which released its nuclear weapon following a mid-air collision.

The bomb was never retrieved, despite initial assertions that it was a dummy, according to National Interest.

The B-47 was transporting a 7,600-pound Mark 15 hydrogen thermonuclear bomb.

The Mark 15 possessed an explosive yield of 3.8 megatons, 190 times more destructive than the Fat Man bomb, which devastated Nagasaki and forced Imperial Japan's surrender.

The F-86's wing was torn off, though the pilot ejected to safety, while the B-47 suffered considerable damage and the pilot feared the bomb could detonate.

As a result, the pilot dropped the Mark 15 into the waters of Wassaw Sound, near Tybee Island.

Deploying sonar equipment, more than 100 Navy personnel scoured the area in search of the discarded Mark 15. The search effort lasted two months, yet nothing was recovered.

The Air Force publicly announced that the bomb's plutonium warhead had been removed prior to the flight and replaced with a lead substitute.

However, decades later, in 1994, declassified documents from a 1966 Congressional testimony revealed that the Tybee Mark 15 was in fact a fully intact nuclear weapon.

In 1966, a B-28 thermonuclear bomb was lost beneath the Mediterranean Sea following a collision between two US military aircraft, and its warhead has never been recovered.

A Spanish shrimp fisherman witnessed the misshapen white package plummet into the sea. It was one of four B-28 thermonuclear bombs scattered following a mid-air collision between two US military aircraft over the Mediterranean.

Three of the B-28s were retrieved on land, but the warhead has never been located.

Tybee, along with the Mediterranean incident, are just two of 32 officially documented "broken arrow" accidents.

Broken Arrow is military terminology for any accidental event involving nuclear weapons, including the loss of a nuclear weapon or the unintended detonation of one.

While Iran's nuclear programme appears to have been substantially crippled by US airstrikes and a prior joint US-Israel operation, concerns are mounting that it may only be a question of time before the country rebuilds its capabilities.

Global security expert Jeffrey Lewis warned: "If the strike does not succeed in removing a regime there remain thousands of people in Iran capable of reconstituting a programme like this.

"The technology itself is decades old, and a vengeful Iran is likely to reach the same conclusion that North Korea reached - that it's a dangerous world with the United States, and it's better to go nuclear."