Military bracing for attack on U.S. forces in Iraq on one year anniversary of strike that killed Iranian top general Qasem Soleimani

One year after U.S. forces assassinated Iranian revered general Qasem Soleimani, a senior official warned Wednesday that the 'threat' coming from Iran is the 'most concerning' yet.

'I would tell you that the threat streams are very real,' the senior official told The Washington Post, warning there is concern of a 'complex attack'.

The official also characterized the situation as the 'most concerning that I have seen' since Soleimani's killing on January 3, 2020.

Specifically, U.S. officials are bracing for an attack from Iran on U.S. forces and troops in Iraq as tensions between Iraq's Washington-backed premier and pro-Tehran forces appeared to have reached a boiling point.

These pro-Iranian forces accuse Iraq's Prime Minister Mustafa Al-Kadhimi of complicity in the Baghdad drone strike.

The Middle Eastern leader has urged calm but warned: 'We are ready for a decisive confrontation if necessary'.

President Donald Trump sent shock waves through the region almost one year ago to the day with the targeted killing of Soleimani and his Iraqi lieutenant, which infuriated the Islamic republic and its allies.

Military leaders are concerned there could be an attack in the coming days against U.S. troops in Iraq as the one year anniversary approaches of the drone strike that took out Iranian General Qasem Soleimani. Here soldiers keep watch on the U.S. Embassy in Baghdad

President Donald Trump is returning from his Mar-a-Lago vacation early on Thursday, with some claiming he could be skipping his New Year's Even Gala in part because of the threat of a retaliatory attack

Pro-Iranian demonstrators gather two weeks after Iranian General Qasem Soleimani (left on banner) and Iraqi paramilitary commander Abu Mahdi Al-Muhandis (right on banner) were killed in a U.S. drone attack in Iraq. Banner reads 'Death to America' in Persian

The threat is so great that some feel it is contributing to why Trump has decided to return to Washington D.C. early on Thursday and skip out on his annual New Year's Eve Gala in Mar-a-Lago.

Trump was vacationing at his South Florida club when he ordered the Soleimani strike at the start of 2020, and at one point said during his trip this year that he is concerned Iran could retaliate for the strike in the coming days.

The president said the drone strike on January 3 came in response to a hail of attacks on U.S. interests in Iraq, which has since continued.

With only weeks left in the White House, the president has warned on Twitter that if there are new attacks, 'I will hold Iran responsible'.

During Trump's presidency, the U.S. has reduced the number of staff at the Embassy in Baghdad and warned of consequences if any Americans are killed.

Iraqi officials are still concerned, however, of a possible confrontation between the U.S. and Iran on Iraqi soil in the closing days of the Trump administration.

On December 20, nearly two dozen rockets were launched at the U.S. diplomatic compound in Iraq, with at least one Iraqi civilian living nearby killed.

Vehicles and buildings on the American site were damaged, the senior U.S. official said.

The attack is among several recently where Iran denied any involvement even as U.S. officials assessed that the rockets were launched by militias coordinating with Iran.

Trump responded by tweeting a warning: 'Our embassy in Baghdad got hit Sunday by several rockets. Three rockets failed to launch. Guess where they were from: IRAN. Now we hear chatter of additional attacks against Americans in Iraq. Some friendly health advice to Iran: If one American is killed, I will hold Iran responsible. Think it over.'

Donald Trump warned last week on Twitter that there is 'chatter of additional attack against Americans in Iraq' after blaming Iran for launching nearly two dozen rockets at the U.S. Embassy in Baghdad

If there are more attacks on U.S. forces in Iraq, Trump said: 'I will hold Iran responsible'

Iran's foreign minister Mohammad Javad Zarif responded on Twitter, writing Trump had 'recklessly' accused Iran of the attack.

'Trump will bear full responsibility for any adventurism on his way out,' Zarif posted.

War-scarred Iraq remains torn between former occupation power, the United States and neighbouring Iran, Washington's arch-enemy, whose influence has increased greatly since the U.S.-led invasion that toppled Saddam Hussein in 2003.

Iraq's Prime Minister Mustafa al-Kadhemi, who took office in May, has recently endured blistering threats from the powerful pro-Iranian paramilitary groups which Washington blames for the rocket attacks.

Security sources say tensions flared after the arrest of a man who planned another attack on the US embassy, a fighter of Asaib Ahl al-Haq , a faction of the Hashed al-Shaabi paramilitary network.

Outraged AAH fighters spread out through Baghdad's streets and threatened to personally target Kadhemi unless their brother-in-arms was let go, the sources said.

'We warn Kadhemi that if you don't back off, you will be punished,' said a masked, gun-toting fighter in one of several videos circulating online.

Another group threatened to 'cut off the ears... of the traitor'.

Pro-Iran forces accuse Kadhemi, who is also Iraq's spy chief, of complicity in the killing of Soleimani, who was head of external operations for Iran's Revolutionary Guards, and Hashed's deputy leader Abu Mahdi al-Muhandis.

Kataeb Hezbollah, another hardline Hashed faction, has piled on the pressure, with a spokesman urging 'treacherous Kadhemi not to test the patience of the resistance'.

The war of words between pro-Iran and Iraq sides have heightened tensions in a country that remains politically fragile after years of war and insurgency and is battling the coronavirus pandemic with its economy reeling from the sharp fall in world demand for oil. 

Lacking the political and military might for a direct showdown, the Iraqi government has instead opted for dialogue.

The prime minister's top interlocutor with Iran, Abu Jihad al-Hashemi, was in Tehran last week to try to mediate, a top Iraqi official told AFP.

A destroyed vehicle remains on fire following the US strike on January 3 on Baghdad international airport road in which top Iranian commander Qasem Soleimani was killed along with eight others

He likely tried to convince Tehran to stop its allies in Iraq from launching further attacks on US and other foreign diplomatic or military sites, said Jiyad.

The hope is to maintain the relative calm since October when hardline groups agreed to an indefinite halt to attacks after a year of frequent rocket fire and roadside bombs. But such attacks are beginning to resume.

Even during the 'truce', unidentified surveillance drones would fly several times a week over the US embassy and adjacent military compound hosting international troops, a senior US military official told AFP.

The US embassy already withdrew its non-essential staff last year and a few weeks ago slimmed down personnel further in what a top Iraqi official said was a temporary step driven by 'security reservations'.

It could also be a harbinger of more US military action to come, Iraqi and Western officials have told AFP in recent weeks. 

'The US would need to get its staff out before it acts, so that they wouldn't be targeted in any possible retaliation,' one Western diplomat said.

That means, as tensions boil at home, Iraqis are also keeping a nervous eye on Washington in the final weeks before Trump hands over to President-elect Joe Biden. 

US President Donald Trump met Iraqi Prime Minister Mustafa al-Kadhemi in the White House on August 20