CBS News revealed on Tuesday audio of a message broadcast through radio frequencies used by pilots and air traffic control professionals in the United States warning of an attack on the U.S. Capitol, allegedly to avenge Iranian terrorist Qasem Soleimani.

Soleimani, a major general in the Iranian military, was the head of its notorious Quds Force, its international terrorism wing. The Quds Force is a subsidiary of the Islamic Revolutionary Guard Corps (IRGC), a formal branch of the Iranian armed forces and a U.S. designated terrorist organization.

President Donald Trump ordered a fatal airstrike against Soleimani and the head of an Iran-backed Iraqi terrorist organization, the Hezbollah Brigades, on January 3, 2020. The Iranian government and sympathizers in Baghdad organized memorial ceremonies to observe the anniversary of Soleimani’s demise this weekend. Tehran has repeatedly threatened to attack the United States in revenge for the strike.

The audio published by CBS News appears to be of a voice doctored electronically, saying only, “We are flying a plane into the Capitol Wednesday. Soleimani will be avenged.”

The voice did not mention any particular jihadist group, government, or entity hostile to the United States. Soleimani was primarily a hero of the Iranian Islamic regime but had close ties to Iraq’s Popular Mobilization Forces (PMF), a collection of mostly Shiite militias that Baghdad legalized as a formal wing of its armed forces during the war against the Islamic State. He also had close ties to the Lebanese-Iranian jihadist group Hezbollah and the socialist government of Venezuela.

CBS reported that the federal government “does not believe that it is credible” but is nonetheless investigating the threat. As of midday Eastern Time Wednesday, police have not announced any action to prevent an attack like the one described in the threat.

One significant concern for law enforcement is the fact that, to broadcast the threat, one or more suspects breached radio frequencies typically used for pilots to communicate with air traffic control. Access to those frequencies could allow a malicious actor to send incorrect instructions to a pilot, causing a disaster.

At press time, police have not identified any individuals with links to the threat, nor have they explicitly blamed the Iranian government prior to his demise, Soleimani would have likely been the official senior enough to handle as sophisticated an operation as an attack on the U.S. Capitol.

Trump issued the order to eliminate Soleimani while the latter was in Baghdad, meeting with Hezbollah Brigades leader Abu Mahdi al-Muhandis, who also died in the strike. A week before that attack, radical Islamists attempted to storm the U.S. Embassy in Baghdad, spray-painting on its walls the message “Soleimani is our commander.”

“Soleimani was the Iranian Regime’s most ruthless butcher, a monster who murdered or wounded thousands of American service members in Iraq,” President Donald Trump said during his 2020 State of the Union address. “As the world’s top terrorist, Soleimani orchestrated the deaths of countless men, women, and children. He directed the December assault on United States Forces in Iraq, and was actively planning new attacks.”

The Iranian government has spent much of the past year vowing revenge for Soleimani.

“You’ll taste this reality that Martyr Qasem Soleimani is more dangerous than Haj Qasem Soleimani,” Lawmaker Ahmad Hamzeh threatened a year ago, offering $3 million to anyone who could kill President Donald Trump.

“Will your embassies in the region be safe? If your embassies are plotting to kill our innocent people, are we allowed to destroy them?” Hamzeh asked. “Are your military bases and centers in the region for benevolence or to harm nations? Are we allowed to destroy all your bases in a preventive attack?”

Iranian state media also broadcast propaganda videos showing Iranian death squads executing Trump, promising Islamic regime loyalists that Iranian vengeance against Trump would be swift.

Threats continued throughout the year.

“Mr. Trump! Our revenge for the martyrdom of our great general [Soleimani] is certain. It is serious. It is real,” Major-General Hossein Salami, the commander of the IRGC, said in September. “We will hit those who were directly or indirectly involved in the martyrdom of this great man.”

“If a hair is missing from an Iranian, we will burn all of your hair. These threats are serious. We won’t do verbal fights. We will leave everything to the field of action. We will go on, with confidence and strength,” he vowed.

In reality, without Soleimani, the Iranian state has largely failed to maintain its violent influence in the Middle East, which it had most effectively administered in Syria, Iraq, Yemen, and Lebanon. This January, Iranian officials reaffirmed their commitment to revenge against Trump, but instead claimed they would prosecute Trump and all involved in the decision to kill Soleimani — presumably in absentia unless Trump chooses to visit Iran.

PMF supporters in Baghdad held a thousands-strong rally to honor Soleimani and al-Muhandis this weekend, featuring anti-American speeches from Iran-backed leaders. The head of Hezbollah, Hassan Nasrallah, independently delivered a speech claiming that Soleimani’s death has led jihadists to become “more determined and strong-willed” against America.

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