The Defense Department is sending six B-52 bombers to the Diego Garcia military base in the northern Indian Ocean as preparations for possible military action against Iran move forward.

Pentagon officials told CNN on Monday that the B-52 will be available for operations against the Islamic Republic if ordered into action, though the deployment does not signal a decision has been made about any attack plans.

The United States maintains several military bases in a number of Middle Eastern countries in close proximity to Iran, but it chose to deploy its bombers to Diego Garcia because it is out of reach of Iran’s longest range missiles, according to the Pentagon.

This is the second time in the last year that the American military has deployed B-52 bomber aircraft to the region due to rising tensions with Iran.

In May, the White House ordered six B-52s to deploy to an American military base in Qatar as well as other bases in ‘southwest Asia’ after it received reports of alleged threats from Iran.

The Pentagon is deploying six B-52 Stratofortress bombers (like the ones seen in the above stock image) to a military base in the northern Indian Ocean, according to a CNN report from Monday

The strategic bombers were on their way Monday to Diego Garcia, an atoll that is home to a vital US military base

Diego Garcia, which is located about 1,000 miles off the southern tip of India, is more than 3,000 miles from Iran. The Pentagon says the base was chosen as the site where the aircraft will be deployed because it is out of range of Iranian missiles

Unlike US military bases in the Middle East, Diego Garcia is out of range of Iran's most advanced missiles. The map above shows Iranian missile capabilities

Diego Garcia: America's most vital military base in the Indian Ocean Diego Garcia is a British Indian Ocean Territory and the largest of the islands in the Chagos Archipelago about 1,000 miles south off the coast of India The Chagos Islands were colonized by France in the 18th century and African slaves were shipped in to cultivate coconuts. In 1814, France ceded the islands to Britain, which in 1903 merged them with Mauritius, its colony about 1,200 miles to the south-west. In 1965, Britain separated the Chagos Islands from Mauritius, paying £3million for them. When Mauritius became independent in 1968, the islands remained under British control, and were renamed the British Indian Ocean Territory. In 1966, Britain leased the islands to the United States for 50 years. Between 1968 and 1973, about 2,000 Chagos islanders were evicted. Most were shipped to Mauritius and the Seychelles. Evicted islanders enlisted the help of human rights lawyer Amal Clooney when they took their fight to the Supreme Court in 2015, but the court ruled against them. The secretive military base on Diego Garcia, the largest island, has been dubbed 'the Guantanamo of the East' amid suspicions it was a key staging post in the US rendition and torture program. In 2016, the US lease was extended to 2036. The American presence there can be attributed to the fact that Diego Garcia's location is strategically vital. Diego Garcia has been a launching point for US military actions in the Middle East - including the 2001 campaign against Afghanistan following the September 11 attacks and the 2003 invasion of Iraq. The horseshoe-shaped atoll of Diego Garcia (right) measures about 17 square miles. It is surrounded by about 60 other atolls. The coastline of Diego Garcia form a natural harbor, making it ideal to station a naval base there It is also a refueling station for Air Force jets that patrol the South China Sea. Diego Garcia was also designated an emergency landing spot for space missions by NASA. The future of the American presence on the atoll was thrown into doubt earlier this year when a United Nations court ruled that the British illegally seized control of the island. The court, in a nonbinding ruling, said that control over the territory should be returned to Mauritius. Diego Garcia is home to between an estimated 3,000-5,000 American military personnel. There is also believed to be a small number of British soldiers stationed at the site as well as civilian contractors mostly from Mauritius. This satellite image taken in 2006 shows B-52s and KC-135s on the ramp at Diego Garcia These contractors are believed to cook and clean for the soldiers and sailors. The horseshoe-shaped atoll measures about 17 square miles. It is surrounded by about 60 other atolls. The coastline of Diego Garcia form a natural harbor, making it ideal to station a naval base there. Diego Garcia is also a tropical paradise that is home to a significant population of turtles, giant migrating birds, and coconut crab. The US military has long been tight-lipped about Diego Garcia. Unlike the base in Guam, spouses of military personnel are not allowed on the atoll. It was also reported that Diego Garcia was used as one of the CIA's 'black sites' - the secret rendition program in which the Americans interrogated and tortured suspected Islamic extremists. But its most important function for the American military is the airstrip. The runways at Diego Garcia allow US warplanes to freely operate in the skies above Africa to the southwest; the Middle East and Central Asia to the north and west; and the Far East and Asia to its east. Source: Business Insider Advertisement

Diego Garcia is a large atoll that hosts a US military base. The atoll is located about 1,000 miles off the southern tip of India.

A Pentagon official told CNN on Monday that aircraft is being deployed to Diego Garcia this time in order to keep the planes out of the range of Iranian missiles.

The Diego Garcia base is part of the British-held territory of Chagos Islands, which legally falls under the rule of Mauritius.

Mauritius is an east African island country in the Indian Ocean located about 700 miles from the coast of Madagascar.

The Chagos base was constructed after the UK ousted more than 2,000 island natives from their homes and leased the grounds to the US.

The Americans have been using the base for more than 50 years.

Iran, which has vowed revenge against the US for the drone strike which killed the commander of the elite Quds Force, Qassem Soleimani, has the capability to reach several American bases, ports, and other installations in the region.

On Twitter, flight trackers noticed that two US Air Force B-52 bombers were over the Atlantic Ocean after departing Barksdale Air Force Base in Louisiana on Monday

The American military footprint in the Middle East and central Asia includes approximately 14,000 troops in Afghanistan; 13,000 soldiers in Kuwait; 13,000 more in Qatar; 7,000 in Bahrain; 6,000 in Iraq; 5,000 in the United Arab Emirates; 3,000 in Saudi Arabia; 3,000 in Jordan; and 2,500 in Turkey.

There are much smaller troop levels in Syria and Oman, according to The Washington Post.

In total, Iran could conceivably strike at areas that would place more than 55,000 American soldiers at risk.

Its ballistic missile arsenal includes weapons that are very difficult to target because they are either road-mobile or hidden inside highly fortified mountain fortresses, according to The War Zone.

In the event of war between Iran and either the United States or its Sunni Arab allies, the Iranians would only need a few minutes to launch ballistic missiles from subterranean strongholds.

Any conflict with Iran would most likely include a US deployment of its B-2 stealth bomber, though there are no reports indicating that the Pentagon has forward deployed these planes to the region. A B-2 bomber is seen above dropping a GBU-57 Massive Ordnance Penetrator

Iran could hit American bases, airfields, and other key sites.

That is why the Pentagon would most likely rely on its fleet of strategic bombers based in Diego Garcia.

If war did break out with Iran, the US has at its disposal machines of war like the B-52 and the B-2 Spirit bombers that can unleash devastating blows.

The Americans would most likely deploy the B-2s to drop precision-guided 40,000-pound 'bunker buster' GBU-57 Massive Ordnance Penetrators (MOPs), which are specially designed to pierce through Iran’s mountain complexes.

There has been no indication from the Pentagon that it has forward deployed B-2s with Iran in mind.

The deployment of the B-52s comes amid tensions in the region stoked by the killing of Soleimani in Baghdad on Friday.

‘Iraq’s parliament called on Sunday for US and other foreign troops to leave as a backlash grows against the strike.

The B-52 Stratofortress: America's long-range strategic bomber A US Air Force B-52 Stratofortress heavy bomber drops bombs in this undated file photo The United States Air Force currently has 76 B-52 Stratofortress bombers in service today. Designed and built by the Seattle-based Boeing Company, the B-52 is a long-range strategic bomber that has been used by the Air Force since the 1950s. It is capable of carrying up to 70,000 pounds of weapons while flying at a combat range of more than 8,800 miles without aerial refueling. This heavy bomber is powered by 8 turbofan engines manufactured by Pratt & Whitney. Each engine is capable of producing 17,000 pounds of thrust to propel the plane forward in the air. The B-52 also boasts a wingspan of 185ft. Each aircraft has a length measuring 159ft4in. The plane stands at a height of 40ft8in. The aircraft weighs approximately 185,000 pounds. It can take off at a maximum weight of 488,000 pounds. To fly its long-range bombing missions, it needs fuel - a lot of it. Each B-52 has a fuel capacity of 312,197 pounds. The plane is a subsonic aircraft that can reach speeds of 650mph. It can also fly at a top altitude of 50,000ft. Source: Boeing Company Advertisement

President Donald Trump responded on Sunday by doubling down on threats to target Iranian cultural sites if Tehran retaliates.

Deepening a crisis that has heightened fears of a major Middle East conflagration, Iran said it was taking another step back from commitments under a 2015 nuclear deal with six major powers.

Iran’s most prominent general, Soleimani, was killed on Friday in a US drone strike on his convoy at Baghdad airport, an attack that carried US-Iranian hostilities into uncharted waters.

Tensions in the Middle East have soard since a top Iranian general, Qassem Soleimani (pictured), was killed in a US drone strike near Baghdad airport on Friday, shocking the Islamic Republic

Iranian state media said 'millions' of people had gathered in Tehran to mourn Soleimani's death in scenes not witnessed since the death of revolutionary leader Ayatollah Ruhollah Khomeini in 1989

An Iranian government minister denounced Trump as a ‘terrorist in a suit’ after the US president sent a series of Twitter posts on Saturday threatening to hit 52 Iranian sites, including targets important to Iranian culture, if Tehran attacks Americans or US assets to avenge Soleimani’s death.

Talking to reporters aboard Air Force One on the way to Washington from Florida on Sunday evening, Trump stood by those comments.

‘They’re allowed to kill our people. They’re allowed to torture and maim our people. They’re allowed to use roadside bombs and blow up our people. And we’re not allowed to touch their cultural sites? It doesn’t work that way,’ he said.

Democratic critics of the Republican president have said Trump was reckless in authorizing the strike, and some said his comments about targeting cultural sites amounted to threats to commit war crimes.

Many asked why Soleimani, long seen as a threat by US authorities, had to be killed now.

Republicans in Congress have generally backed Trump’s move.

Trump also threatened sanctions against Iraq and said that if US troops were required to leave the country, Iraq’s government would have to pay Washington for the cost of a ‘very extraordinarily expensive’ air base there.

He said if Iraq asked US forces to leave on an unfriendly basis, ‘we will charge them sanctions like they’ve never seen before ever. It’ll make Iranian sanctions look somewhat tame.’

Iran's Supreme Leader Ayatollah Ali Khamenei (center) leading a prayer as President Hassan Rouhani (fifth right) perform the prayer over the caskets of slain Iranian military commander Qassem Soleimani and Iraqi paramilitary chief Abu Mahdi al-Muhandis at Tehran University on Monday

The Iraqi parliament passed a resolution calling for an end to all foreign troop presence, reflecting the fears of many in Iraq that Friday’s strike could engulf them in another war between two bigger powers long at odds in Iraq and across the region.

While such resolutions are not binding on the government, this one is likely to be heeded: Prime Minister Adel Abdul Mahdi had earlier called on parliament to end foreign troop presence as soon as possible.

Iran and the United States have been competing for clout in Iraq since the US-led invasion in 2003 that toppled dictator Saddam Hussein.