NORTH Korea has said it has suspended nuclear and long-range missile tests ahead of a new round of negotiations with South Korea and the United States.

Pyongyang said it also plans to close its nuclear test site, although there was no clear indication if it would be willing to part with its arsenal.

Leader Kim Jong Un declared the nation's nuclear force as complete in November after a slew of weapons tests that included the underground detonation of a purported thermonuclear warhead.

North Korea had also carried out flight tests of three intercontinental ballistic missiles.

Some analysts believe Mr Kim is entering the negotiations from a position of strength and is unlikely to accept a significant cut to his arsenal or go significantly beyond freezing a nuclear programme.

South Korean and US officials have said Kim is likely trying to save his broken economy from heavy sanctions.

After the announcement on Saturday about testing, US President Donald Trump tweeted: "This is very good news for North Korea and the world," adding "big progress!"