Military action against North Korea 'not inevitable: Trump

US military action to deal with North Korea's nuclear threat is not "inevitable" says Donald Trump, but he warns diplomatic efforts are failing.

North Korean leader Kim Jong Un on April 15, 2017, in Pyongyang, North Korea, left, and U.S. President Donald Trump in Washington on April 29, 2017. Source: AAP

President Donald Trump says he'd prefer to avoid military action to deal with North Korea's nuclear threat, but says previous diplomatic efforts have failed to pressure Pyongyang from developing its missiles.

"Military action would certainly be an option. Is it inevitable? Nothing is inevitable," Trump said during a news conference on Thursday.

"I would prefer not going the route of the military," Trump said. "If we do use it on North Korea, it will be a very sad day for North Korea."