Belgium - Armed forces from 14 NATO member states began annual exercises on Monday to simulate the defense of the territory covered by the alliance using nuclear weapons.

The exercises, called Steadfast Noon, involve up to 60 of aircraft, including fighter jets, surveillance and refueling aircraft, as well as long-range B-52 bombers from the US, that will fly from North Dakota, according to NATO.

Training flights will take place over Belgium, which is hosting the exercise, as well as over the North Sea and the UK, NATO said. No live weapons are used, NATO stressed.

Steadfast Noon "is a routine, recurring training activity and it is not linked to any current world events," a press release read.

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Steadfast Noon is hosted by a different NATO ally each year, spokesperson Oanan Lungescu said.

"This exercise helps ensure that the alliance's nuclear deterrent remains safe, secure and effective," Lungescu said.

Under NATO's nuclear sharing program, US nuclear weapons stationed in Europe can also be used by partner states' aircraft in an emergency to combat enemy forces, for example.

US nuclear weapons are also stored in Belgium, Turkey, the Netherlands, and Germany, according to information that has not been officially confirmed by the alliance.