Several United States nuclear-command aircraft, commonly referred to as 'doomsday planes,' were observed flying over the U.S. on Tuesday, a development that occurred hours after CIA Director John Ratcliffe made an unannounced visit to Moscow.

Flight tracking enthusiasts reported seeing at least five Boeing E-6 Mercury aircraft over the West Coast and central regions of the United States. These aircraft, built on the frame of the Boeing 707, are equipped to operate and coordinate military responses from the air in the event of ground-based attacks during a nuclear war.

Public flight trackers began observing the planes around 1:30 p.m. EST, with many appearing on ADS-B services with blank or missing call signs. The flights followed Ratcliffe's trip to Moscow, which had already drawn attention after a U.S. Air Force Boeing C-17A Globemaster III transport plane was spotted landing at Vnukovo International Airport, an unusual occurrence given current geopolitical tensions between Washington and Moscow.

Officials have not released any statements regarding the sightings of the E-6 Mercury aircraft or announced any accompanying military exercises. While seeing five such planes in the sky is noteworthy, the U.S. Navy routinely flies six E-6Bs for training purposes.

FlightRadar24 data indicated specific flight paths for several of the aircraft. One plane, identified by hex code AEA92D, was tracked over the Colorado-Wyoming region at an altitude of approximately 24,000 feet and a speed of about 374 mph. Another, AE7D28, flew over the central U.S. near Kansas and Oklahoma at roughly 30,000 feet, reaching speeds of around 471 mph.

The aircraft designated AEABAB was observed over Missouri and Arkansas at an altitude of approximately 35,000 feet, traveling at 541 mph. Additionally, AF4019 was tracked near the Texas-Oklahoma border at a lower altitude of about 9,500 feet, moving at 307 mph, which may suggest it was in a climbing or different phase of flight. A fifth aircraft, AF1BB0, was flagged as a potential E-6 Mercury, though its identification was not consistently confirmed across tracking data.

The E-6 Mercury, also known by the call sign 'Take Charge And Move Out,' is a critical asset for the National Command Authority, responsible for maintaining communication with ballistic missile submarines at sea.