• President Donald Trump threatened Iran with bombing like "they have never seen before" over the weekend.
• His threat came amid the unusual deployment of B-2 stealth bombers to the Indian Ocean.
• The bombers arrived amid a larger build-up of US military assets in the Middle East area.

President Donald Trump is threatening Iran with bombing to get to a new nuclear deal.

The threat comes as the US appears to be massing B-2 stealth bombers at a strategic base in the Indian Ocean that has been used to stage strikes in the Middle East.

"If they don't make a deal, there will be bombing," Trump told NBC News' Kristen Welker over the weekend, adding that "it will be bombing the likes of which they have never seen before."

Earlier this month, Trump gave Tehran a two-month deadline to agree to a new nuclear deal or face military action. On Sunday, Iran's President Masoud Pezeshkian rejected direct talks with the US, though he left the door open to indirect negotiations.

Trump withdrew from a landmark 2015 nuclear deal with Iran during his first term in office.

The president's threat comes as the US has been deploying B-2 Spirit bombers to Diego Garcia, a tiny British island in the Indian Ocean that has served as a joint UK-US military base for decades, in an unusual move. Open-source intelligence analysts began tracking the arrival of multiple aircraft over the past few days.

A spokesperson for Air Force Global Strike Command confirmed that there are B-2s at Diego Garcia, though they would not say how many. Recent satellite imagery indicated that as of last Tuesday, there were at least three of them there, but possibly more.

"Their mission is to deter, detect, and, if necessary, defeat strategic attacks against the United States and its allies," the spokesperson told Business Insider on Monday without elaborating further.

The bombers could be there in relation to developments in the Middle East or Bomber Task Force missions. Either way, it's a lot of firepower readily available.

The B-2 Spirit is a long-range strategic bomber manufactured by Northrop Grumman. The Air Force has just 19 of these stealth aircraft in active service. Built for penetrating strikes against hard-to-reach targets, the bombers are based at Whiteman Air Force Base in Missouri.

The roughly $2 billion B-2 is capable of delivering both nuclear and conventional strikes and is able to carry up to 40,000 pounds of ordnance, including the GBU-57 Massive Ordnance Penetrator. The MOP is a 30,000-pound bunker buster.

It's been speculated that an attack on Iran's nuclear facilities, which are largely underground in hardened bunkers, would require capabilities only that the B-2 can deliver.

The specific purpose of the B-2s on Diego Garcia is unclear, but they have the potential to serve as a show of force for Iran and its proxies. Last fall, the US sent a clear message to Tehran by sending B-2 bombers to strike hardened Houthi facilities. Iranian support for the Houthis has fueled the Red Sea crisis, which has heated up again lately.

The Trump administration has pounded the Iran-backed rebels with airstrikes over the past two weeks in an effort to stop their attacks against military and civilian vessels in the Red Sea and Gulf of Aden.

However, the Houthis demonstrated as recently as Sunday that they can still fire long-range missiles at Israel, which they continue to do in protest of the Gaza war.

The deployment of the B-2s noticeably comes amid a larger US military build-up in the Middle East. There have been rising tensions and threats between Trump's White House and Iran and the Tehran-backed Houthis.

On Saturday, the Idaho Air National Guard's 124th Fighter Wing announced the deployment of more than 300 Airmen and several A-10 Thunderbolt II attack aircraft to the Middle East area of operations. The unit has previously deployed in support of the US-led war against the Islamic State.

The Navy is also sending a second aircraft carrier to the region. USS Carl Vinson will join the USS Harry S. Truman and its strike group, which has been striking the Houthis for weeks. When it arrives, the Vinson would be the fifth US carrier to partake in combat operations against the rebels.

• Israel would need US help if it set out to destroy Iran's underground nuclear sites.
• The operation would require repeated cruise missile strikes and heavy, bunker-busting bombs.
• There are limits to what the US and Israel could accomplish in a short air campaign.

Iran can enrich enough uranium for a nuclear weapon within weeks. The options to stop Iran from getting a bomb, if it so chooses, are through a nuclear deal like the one President Donald Trump withdrew from in 2018 or with overwhelming military force.

"There are two ways Iran can be handled, militarily or you can make a deal. I would prefer to make a deal," Trump said in a March 6 interview with Fox News. The US, he said, has "a situation with Iran that's going to happen very soon, very, very soon."

Early signs of a deal were inauspicious. Trump dialed up the pressure on Iran after US strikes on the Iran-backed Houthi rebels in Yemen over the weekend, warning in a Monday Truth Social post that "every shot fired by the Houthis will be looked upon, from this point forward, as being a shot fired from the weapons and leadership of IRAN."

Israel could attempt pre-emptive strikes, but they would likely need US airpower in what would be a major escalation if they aimed to demolish Iran's underground facilities for weapons-grade uranium, according to military analysts.

To wipe out Iran's nuclear facilities, US and Israel would need to carry out repeated strikes with stand-off weapons like cruise missiles, Ryan Bohl, a senior Middle East and North Africa analyst at the risk intelligence company RANE, told Business Insider.

Such strikes could also require the Northrop B-2 Spirit stealth bomber. The B-2 is the only aircraft that can carry the US's 15-ton GBU-57 Massive Ordnance Penetrator, the largest US bunker buster, and one of the most powerful non-nuclear bombs. A B-2 notably bombed hardened underground weapon sites belonging to the Iran-backed Houthis in Yemen in October.

"It would be a major milestone in the history of warfare should we see a joint Israeli-US strike on Iran," Bohl said. "It would give us insight into how such (American-made) systems might also perform against, say, Russia and China, whose systems are in some ways similar to that of Iran's."

The United Nations Security Council discussed Iran's enrichment of uranium near weapons-grade level in a closed meeting on Wednesday. The US accused Iran of "flagrantly" defying the council over its rapid uranium enrichment.

Amid the back and forth between the Trump administration and Iran, a US Air Force B-52 Stratofortess bomber drilled with Israeli Air Force F-35 stealth jets and F-15 fighters. Both air forces have drilled on numerous occasions in recent years in preparation for a possible attack against Iran.

The largest-ever exercise was Juniper Oak in January 2023, when American and Israeli F-35 stealth jets, drones, and US strategic bombers dropped over 180,000 pounds of live munitions.

"Juniper Oak gave us insight into how a maximum escalation scenario might play out with joint Israel-US operations," Bohl said.

Why Israel would likely need US bombers

Israel's fighter fleet consists of fourth-generation American-made F-15 and F-16 jets and more advanced fifth-generation F-35s made by Lockheed Martin. Israel doesn't have heavy bombers capable of carrying large bunker-buster munitions.

The two primary targets of any strikes would be the Natanz and Fordow underground enrichment facilities. Natanz is deep underground and shielded by reinforced concrete in the central Isfahan province. Satellite imagery taken in 2023 indicated Iran has dug tunnels near the site too deep for even the GBU-57 to damage effectively. Fordow is the country's second uranium enrichment facility, which Iran dug inside a mountain to build near the holy city of Qom.

US-Israeli airstrikes would have to be part of a larger, complex campaign that also targets Iranian air defenses and ballistic missiles with air and ship-launched munitions, drones, cyberattacks, and possibly limited special operations raids, according to Nicholas Heras, senior director of strategy and innovation at the New Lines Institute.

Israel already inflicted widespread damage on Iran's Russian-made S-300 air defenses during its October 26 airstrikes. Another round of strikes, especially with American participation, could prove much more devastating.

"Iran is on the back foot defending its airspace," RANE's Bohl said.

While Iran's antiquated air force is outclassed and outgunned by the USAF and IAF, there are still limits to what the latter's cutting-edge airpower can achieve, especially if America and Israel are reluctant to conduct a long campaign. And if a US-Israeli campaign does not broadly target Iran's military arsenal, Tehran could mount substantial retaliation.

For years, the country has possessed the largest arsenal of ballistic missiles in the region. While these missiles failed to inflict significant damage during Iran's April and October 2024 attacks against Israel, they could still menace US bases in the Middle East or force Israel to expend more of its expensive and finite high-altitude Arrow anti-ballistic missile interceptors in order to fend them off.

Iran has had decades to prepare for such an attack.

It's possible "Iran is able to weather the worst of it and rebuild," since bombs and missiles can fail to destroy all of the Iranian centrifuges used to enrich uranium, Bohl said.

Either way, a joint air assault against Iran could prove unprecedented.

"Without a doubt, a joint US-Israel military campaign against Iran's nuclear program would be one of the largest, and certainly the most technologically advanced, in human history," New Lines Institute's Heras said.

Paul Iddon is a freelance journalist and columnist who writes about Middle East developments, military affairs, politics, and history. His articles have appeared in a variety of publications focused on the region.