North Korea has reportedly launched a ballistic missile just hours after the United Nations met to discuss the country's nuclear threat.

"North Korea fired an unidentified missile from a site in the vicinity of Bukchang in Pyeongannam-do (South Pyeongan Province) early this morning," South Korea's Yonhap reported, quoting a statement issued by the military.

A US government source told Reuters that initial indications were that the test was unsuccessful.

US President Donald Trump has warned there is a chance of a "major, major conflict" with North Korea due to rising tensions over its nuclear ambitions and missile tests.

The US President said he would "love to solve things (the North Korean problem) diplomatically but it's very difficult".

And at the UN meeting in New York US Secretary of State Rex Tillerson urged the Security Council to put economic and diplomatic pressure on Pyongyang.

He said it was only a "matter of time" before the communist state was capable of hitting mainland America with a nuclear weapon.

Speaking after the meeting, North Korea's deputy ambassador to the UN said the country's nuclear weapons would never be part of "political bargains and economic deals".

"In a nutshell, DPRK have already declared not to attend any type of talks which would discuss its nuclear abandonment, nuclear disbandment," Kim In Ryong said.

He added that the nuclear programmed "is the product of the United States' hostile policy towards DPRK".