As the tensions between Israel and Iran escalate, an Iraqi terror group said all US nationals in the Middle East will be legitimate targets if Donald Trump was to assassinate Iran's Supreme Leader, reports The Mirror. Iraq's top Shiite Muslim cleric Grand Ayatollah Ali Sistani warned against targeting Iran's leadership. He said the ongoing Israel-Iran conflict could plunge the whole region into chaos, according to AFP.Sistani said in a statement Thursday that any targeting of Iran's supreme religious and political leadership would have dire consequences on the region .ALSO READ: Amazon's 30-day deadline to employees amid mass layoff fear: Resign in 60 days or...US nationals on alert amid Israel-Iran conflictIn recent days, US and its strong ally Israel have hinted that there could be plans to assassinate Iran's religious patriarch Ayatollah Ali Khamenei- a respected figure across the Shiite world. In response to this, Akram al-Kaabi - who rules the powerful Iraqi Shiite militia Karakat Hezbollah al-Nujaba - has said any threat to Khamenei's life would see American people and their allies become legitimate targets anywhere in the region.ALSO READ: Amid Israel-Iran conflict, Ayatollah Ali Khamenei's bizarre posts re-surface. Internet is in complete disbeliefIn a stern warning, Akram al-Kaabi said such action against the Shiite-led Islamic republic could spark widespread chaos that would exacerbate the suffering of its (the region's) people and severely harm everyone's interests . Sistani urged the international community to make every effort to end this unjust war and find a peaceful solution to concerns about Iran's nuclear programme.Sistani, an Iranian, is the highest religious authority for millions of Shiite Muslims in Iraq and around the world, with the power to mobilise a huge following in Iraq. Despite his Iranian roots, Sistani is seen as a key figure in Iraq's recent history and has been known for pushing back against Tehran's growing clout in the country.Akram warned the United States against going after Khamenei. If you harm a hair of Khamenei's head you and your allies will be under our fire, Kaabi said in a statement. No soldier or diplomat will be spared, Kaabi said. Every person holding your nationality in our region, as well as all your direct or indirect interest will be a legitimate target, he added.ALSO READ: Trump's presidency facing challenges? Organizers of 'No Kings' protests plan another rally on THIS dateThe powerful faction Kataeb Hezbollah said that Trump made a mistake when he spoke of Khamenei and warned the US president of unprecedented calamities and destruction if he goes into war in support of Israel.In Lebanon, Iran-backed militant group Hezbollah warned against threatening Khamenei, describing it as an act of recklessness and foolishness that would have grave consequences .It constitutes an offence to hundreds of millions of believers , added the group, which suffered heavy blows in its latest confrontation with Israel last year.US labelled Iraq group as terror outfitIn 2019, the US officially labelled the organization a terror outfit, introducing sanctions to block connections with either the armed group or its commanding officer. The militia boasts some 10,000 fighters and is involved in military activities in Iraq and Syria as an extension of the larger Popular Mobilization Forces, which operate under Iranian influence.ALSO READ: Amid Israel-Iran conflict and World War III fear, Trump rants about not playing golf for weeksConsidered one of the most aggressive Iran-backed militias in Iraq, Nujaba has emerged as a key armed opponent of the US presence in the country. According to the Washington Institute, the group is reportedly responsible for leading many of the attacks targeting American bases in Syria and Iraqi Kurdistan, The Mirror reports.The militia’s founder and leader, Akram al-Kaabi, has been labeled a Specially Designated Global Terrorist for his close ties to Iran and involvement in repeated assaults on US forces.Defying Trump's warnings that Tehran must accept 'unconditional surrender', Supreme Leader Ali Khamenei threatened 'irreparable damage' to America if it gets involved in the war. This verbal clash occurred as Israel continued its relentless attacks on Iran's nuclear research bases and various military sites with waves of strikes across the country.ALSO READ: 16 billion passwords leaked in largest data breach ever: Check tips to protect your Facebook, Instagram accountsIsrael's Defence Minister Israel Katz said Thursday that Iran's supreme leader Ayatollah Ali Khamenei can no longer be allowed to exist after an Israeli hospital was hit during an Iranian missile attack.Earlier this week, Israeli Prime Minister Benjamin Netanyahu did not rule out plans to assassinate Khamenei.US President Donald Trump had earlier said his country would not kill Khamenei for now , but demanded Tehran's unconditional surrender and warned he was weighing military action in the conflict.(With AFP inputs)