The US just sent a warning to Iran in the form of two B-52H Stratofortress bombers

• The US military sent two US Air Force B-52 Stratofortress bombers flying past Iran on Thursday.
• "Potential adversaries should understand that no nation on earth is more ready and capable of rapidly deploying additional combat power in the face of any aggression," CENTCOM commander Gen. Frank McKenzie said in a statement.
• The flight marks the second long-range bomber deterrence flight through the Middle East in less than three weeks.

Two US Air Force B-52H Stratofortress strategic bombers sent a warning to Iran Thursday with an unexpected fly-by.

The pair of strategic bombers assigned to the 2nd Bomb Wing flew a short-notice, long-range, non-stop flight from Barksdale Air Force Base in Louisiana to the Middle East, US Central Command said in a statement. The 36-hour bomber mission took the aircraft into the Persian Gulf, NBC News and others reported.

Gen. Frank McKenzie, the CENTCOM commander, said that "potential adversaries should understand that no nation on earth is more ready and capable of rapidly deploying additional combat power in the face of any aggression."

"We do not seek conflict," he further explained, "but we must remain postured and committed to respond to any contingency or in opposition to any aggression."

The bombers were accompanied by aircraft from Saudi Arabia, Qatar, and Bahrain at various points in their mission.

McKenzie said that "the ability to fly strategic bombers halfway across the world in a non-stop mission, and to rapidly integrate them with multiple regional partners demonstrates our close working relationships and our shared commitment to regional security and stability."

A senior military official told NBC News that the risk of a miscalculation is "higher than normal right now" given the rocky transition of power to the incoming Biden administration, as well as troop drawdowns elsewhere in the region.

In recent weeks, there have also reportedly been discussions of aggressive US actions toward Iran. Iran's top nuclear scientist was recently assassinated, and the Iranians, noticeably on edge, have pointed fingers at both Israel and the US.

"It doesn't mean that they're going to do something," the senior military official told NBC News. "But, you know, we want to ensure that if they are contemplating some sort of an aggressive act, that they would they would think twice about it before they did it."

Thursday's flight marks the second time in less than a month the US military has sent B-52s into the Middle East on a deterrence mission. A pair of B-52 bombers assigned to the 5th Bomb Wing at Minot Air Force Base in North Dakota conducted a short-notice, long-range flight to the Middle East on Nov. 21.

"The ability to quickly move forces into, out of and around the theater to seize, retain and exploit the initiative is key to deterring potential aggression," Lt. Gen. Greg Guillot, the 9th Air Force (Air Forces Central) commander, said in a CENTCOM statement at the time.

Tensions between the US and Iran boiled over in January, when the US assassinated Maj. Gen. Qassem Soleimani, former commander of the Islamic Revolutionary Guard Corps Quds Force in a drone strike. Iran retaliated with a ballistic missile strike on US and coalition forces in Iraq.

In the aftermath, both sides moved to de-escalate, but tensions have persisted.

The official who spoke to NBC News said that the bomber missions are "specifically designed not to be overly provocative." These flights "demonstrate that we could move additional forces here very quickly, that we have global reach with our bomber task force and that our regional partners support us bringing those sorts of capabilities in from time to time."

US force presence in the region is designed to "make the Iranians realize the stakes of what could be," the official said.