In September, the Pentagon’s senior leadership was briefed by military, intelligence, and law enforcement officials on credible domestic and overseas threats against Washington’s military and civilian leaders, sources reported. These active threats could possibly be related to the assassination of Iranian Major General Qassem Soleimani as Iran may be looking to retaliate.

The briefings, according to media sources, show that security officials believe that senior U.S. leadership involved in the Soleimani assassination has been targeted. NBC News was the first to break the story. 

This week, Defense Secretary Mark Esper has been traveling in the Middle East and South Asia. His security staff kept a tighter lid than usual on any information regarding his itinerary, suggesting that there are heightened security measures in place. Reporters traveling with Secretary Esper were not allowed to report about his visits to Bahrain or Israel until after he left each country, although he spent two nights in Bahrain.

Officials from the FBI, CIA, and the Pentagon first met on September 22 following an incident involving a senior Department of Defense official who had been followed by an Iranian national after leaving the Pentagon.

The American official was in a black government SUV driven by a security detail when an Iranian national, driving a car with Virginia plates, followed him for five to seven miles, driving “aggressively” at times, according to the security detail. The security detail was able to lose the suspected tail by changing routes

There was disagreement between the FBI and the Pentagon on whether this classifies as a serious attempt to target a senior Defense Department leader. The FBI is not considering it a serious concern. Reportedly, it investigated the individual and found no correlation between him and the Iranian government. 

However, the Pentagon and the security detail issued a “Be On the Lookout” (BOLO) for the car and posted pictures of the driver. A subsequent investigation turned up the driver’s Facebook and Instagram pages, showing his friends in both Iran and Afghanistan. The White House refused to acknowledge if the president was briefed on the incident but one administration source told the media that this situation was “concerning.” 

But shortly after the incident, President Trump commented on Twitter, as he often does. “According to press reports, Iran may be planning an assassination, or other attack, against the United States in retaliation for the killing of terrorist leader Soleimani, which was carried out for his planning a future attack, murdering U.S. Troops,” he tweeted.

Pentagon spokesman Jonathan Hoffman spoke to NBC about the seriousness of the situation. “The Department of Defense takes seriously the safety of all of our personnel,” he said. “We will not discuss intelligence regarding potential threats to senior leaders nor the range of force protection measures we have in place to address these threats.”

Regarding the security around the Defense Secretary’s movements, Hoffman added, “security measures [are decided] on a case-by-case basis in coordination with the appropriate U.S. and host nation law enforcement officials to protect our hosts, traveling officials, their support staff and accompanying media. We are constantly evaluating the threat environment.”