The pontiff suggested that Norway, for example, was "always ready to help".
He warned the crisis risked sparking a devastating war in which "a good part of humanity" would be destroyed.
His comments come hours after North Korea test-fired another ballistic missile, which the US and South Korea say exploded shortly after take-off.
The missile was fired from a site in South Pyeongan province, north of Pyongyang, South Korea said.
US President Donald Trump accused Pyongyang of showing "disrespect" towards China and its president.