NATO will push ahead with long-planned nuclear exercises next week despite rising tensions over the war in Ukraine and President Vladimir Putin's insistence that he is not bluffing about using all available means to defend Russian territory, NATO Secretary-General Jens Stoltenberg said Tuesday.

The exercise, dubbed "Steadfast Noon," is held annually and usually runs for about one week. It involves fighter jets capable of carrying nuclear warheads but does not involve any live bombs. Conventional jets, and surveillance and refueling aircraft also routinely take part.

Fourteen of the 30 NATO member countries will be involved in the exercise, which was planned before Russia invaded Ukraine in February. The main part of the maneuvers would be held more than 1,000 kilometers (625 miles) from Russia, a NATO official said.

"It would send a very wrong signal if we suddenly now cancelled a routine, long-time planned exercise because of the war in Ukraine. That would be absolutely the wrong signal to send," Stoltenberg told reporters on the eve of a meeting of NATO defense ministers in Brussels.

"NATO's firm, predictable behavior, our military strength, is the best way to prevent escalation," he said. "If we now created the grounds for any misunderstandings, miscalculations in Moscow about our willingness to protect and defend all allies, we would increase the risk of escalation."