The US Air Force has announced the dismissal of the general in charge of the country's long-range nuclear missiles for poor behaviour.

Major-General Michael Carey was removed from his command of the 20th Air Force due to a loss of trust and confidence due to "behaviour during a temporary duty assignment", the air force said.

The 20th Air Force is responsible for 450 intercontinental ballistic missiles, many of which have multiple warheads.

Brigadier Les Kodlick, US Air Force spokesman, said: "The allegations are not related to operational readiness nor do they involve sexual misconduct."

Two unnamed officials indicated to the AP news agency that it was linked to alcohol use.

Carey's removal comes days after the US Navy announced that Admiral Timothy Giardina had been demoted from second-in-command at Strategic Command, which has control over the US nuclear arsenal, for allegedly using counterfeit casino chips.

The 20th Air Force's management of its missiles has come under intense scrutiny in recent months.

A total of 19 missile crew members at a base in North Dakota were decertified after a "poor showing" in a March inspection.

In August, the 341st Missile wing, based in Montana, was issued a failure grade during an inspection, which cited "tactical-level errors" during one of several exercises.

Cary, a two-star general, has served in the US military for 35 years and was in charge of almost 10,000 people at three military bases.