Updated

Senior U.S. officials revealed Thursday that security threats have been made against top Pentagon authorities not only when traveling outside the U.S., but when on American soil.  

Frist reported by NBC News on Thursday and verified for Fox News by a senior Department of Defense representative, security officials believe the threats made could be linked to the killing of Iranian Gen. Qasem Soleimani by American forces in January, though definitive links could not reportedly be made.

The names of the Pentagon officials were not released, but they are believed to have been senior leadership involved in the operation that oversaw the takedown of Soleimani. Military leaders have also reportedly been targeted.

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A person familiar with the threats told Fox News that U.S. concerns of Iran harming American officials, extends to civilian officials as well.

U.S. military, intelligence and law enforcement were briefed last month alerting them to the threats.

The FBI, CIA and military officials first met on Sept. 22 following an incident that reportedly involved a senior Department of Defense official who was followed by an Iranian national.

The DOD official, who asked not to be identified for security reasons, was followed after getting into a black, government-owned SUV driven by his security detail after leaving the Pentagon.

The driver of the tail, later identified as an Iranian national driving a car with Virginia plates, followed them for five to seven miles, reportedly driving “aggressively” at times.

The security detail was able to lose the suspected tail after changing routes, officials told NBC.

The Pentagon issued a “Be on the Lookout” alert, also known as a BOLO, and informed federal law enforcement authorities of the incident -- releasing details of the Iranian national's Facebook and Instagram accounts, which showed he had friends in Iran and Afghanistan.

Though according to the report by NBC, Pentagon and FBI officials disagree on whether or not the event constitutes an actual attempt to target a senior DOD official.

The FBI allegedly investigated the event and found no relation between the Iranian national and the Iranian government, or any reason to suspect it was a part of a larger security concern.

These findings apparently drew greater concern from Pentagon officials and one senior administration official said the incident was "concerning."

U.S. officials could not address why there was a disagreement on the level of concern surrounding the incident, or confirm whether or not the Iranian driver was questioned or taken into custody.

“The Department of Defense takes seriously the safety of all of our personnel,” Pentagon spokesman Jonathan Hoffman told NBC. “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.”

The CIA and FBI reportedly declined to comment on the incident.

The White House also declined to comment on whether or not President Trump was informed of the event.

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But Trump did release a tweet in mid-September drawing attention to suspected Iranian threats.

“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,” Trump wrote.

Jennifer Griffin and Rich Edson contributed to this report.