"We have the capability and resolve to deter any attack. That's the way NATO has handled ballistic missiles threats in the Cold War," he said.
"NATO is ready to respond [to] and counter any attacks from any direction," he added.
His defiant comments come amid fears North Korea may be about to test the dreaded "Juche Bird” missile – a nuclear warhead strapped to an ICBM.
US officals have confirmed that the communist state is working on the advanced ICBM, thought to be capable of reaching the US.
In the press conference today, Stoltenberg agreed that North Korea is developing ballistic missiles capable of hitting the US mainland as well as Europe.
But despite that severe threat, Stoltenberg said NATO is committed to finding a "peaceful" resolution to the crisis engulfing the Korean peninsula.
The NATO chief is currently on a visit to South Korea to disucss security issues posed by the secretive state and its missile programme.
On Wednesday, he urged the international community to unite against the “global threat” in a meeting with Kang Kyung-wha, South Korean foreign minister.
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