Iran issued chilling warning days before attack telling Trump exactly what it would do if he ordered strike

Iran reportedly made its intentions clear of what it would do if America attacked it in the days leading up to Donald Trump's decision to order air strikes.

On Saturday, President Trump gave the green light for US forces to strike Iran. Three of the country's nuclear sites were hit after 125 aircraft traveled over 7,000 miles to carry out Trump's orders.

In an national address after the strikes, Trump told Americans: "The US military carried out massive precision strikes on the three key nuclear assemblies in the Iranian regime: Fordo, Natanz and Isfahan.

"Our objective was the destruction of Iran's nuclear enrichment capacity and a stop to the nuclear threat posed by the world's number one state sponsor of terror."

The POTUS has also warned Iran that it shouldn't retaliate, stating it 'will be met with force far greater' than than the weekend's strikes.

Donald Trump ordered the US military to attack Iran over the weekend (Tasos Katopodis/Getty Images)

But Iran made remarks on what it would do if America issued air strikes in the days leading up to three of its nuclear sites being targeted, sources said.

According to NBC News, Iran warned Trump that it would activate sleeper-cell terror inside the United States if it were attacked. Reportedly Trump received such a message through an intermediary at the G7 summit in Canada last week.

Sleeper cells are spies and/or terrorists that are already in the US but remain inactive until given direct orders to attack. They often live quiet lives and have regular jobs, says The Independent.

With this chilling warning in mind, New York authorities are said to be on 'heightened alert'.

The city's mayor, Eric Adams, has said: "There are no notable threats directly to the city, but you always want to be conscious of lone wolves."

New York Police will focus its attention on locations tied to Jewish and Persian communities, NBC reports, as well as popular tourist sites like Times Square.

Adams added: "We want to make sure no lone wolf attacks happen at those locations."

He further assured New Yorkers that they're 'stepping up'.

Several world leaders have weighed in on the ongoing conflict, with British Prime Minister Keir Starmer urging Iran to return to negotiations.

Iranian Supreme Leader Ali Khamenei warned about how it would retaliate if the US attacked (Office of the Supreme Leader of Iran via Getty Images)

The PM spoke to Trump on Sunday night after the attack on Iran, with Downing Street revealing the leaders agreed Tehran must not be allowed to develop a nuclear weapon and called for the nation to return to negotiations.

"The leaders discussed the situation in the Middle East and reiterated the grave risk posed by Iran’s nuclear programme to international security," Downing Street said.

"They discussed the actions taken by the United States last night to reduce the threat and agreed that Iran must never be allowed to develop a nuclear weapon.

"They discussed the need for Iran to return to the negotiating table as soon as possible and to make progress on a lasting settlement.

"They agreed to stay in close contact in the coming days."

The Israel-Iran conflict summarised

Israel launches attack

Despite relations between Israel and Iran being tense for years now, it reached new heights on June 13 when Israel launched a large-scale attack on Iranian military and nuclear sites, killing nuclear scientists and high-profile military officials.

Israel argued that Iran could make a nuclear weapon quickly, citing it as the reason for the attack.

Iran retaliates

Iran responded by firing a barrage of missiles back at Israel, some of which were able to penetrate Tel Aviv's Iron Dome air defence system.

It's sparked a back and forth of attacks between the nations which have so far killed at least 950 people in Iran, including 380 civilians, according to Human Rights Activists. Meanwhile, Israel said 24 people have been killed as a result of Iranian strikes on the nation.

US wades in

On Saturday night, Trump ordered bombing attacks on Iran's Fordow, Isfahan and Natanz nuclear sites, branding the strikes a huge 'success'.

It came after Trump threatened Iran with the 'might' of the US Armed Forces, saying it would come down at 'levels never seen before' should Iran strike the US in any way.

Iran says US will face 'everlasting consequences'

Iran's Foreign Minister Seyed Abbas Araghchi posted on social media that the US 'committed a grave violation of the UN Charter, international law and the NPT by attacking Iran's peaceful nuclear installations'.

"The events this morning are outrageous and will have everlasting consequences. Each and every member of the UN must be alarmed over this extremely dangerous, lawless and criminal behavior," he added.

Iranian officials confirmed the three facilities were struck in the US' attack but denied any major damage was done, while Trump claimed they'd been 'obliterated'.