North Korea has celebrated the anniversary of its founder's birth with a festival of flowers, easing tensions in a region that had seemed on the verge of conflict.

The North has threatened nuclear attacks on the United States, South Korea and Japan in recent weeks, after new UN sanctions were imposed in response to its latest nuclear arms test in February.

Many analysts had expected a big military parade to showcase the North's armed forces on the "Day of the Sun".

However, the 101st anniversary of Kim Il-sung's birth was marked in the capital, Pyongyang, with a festival of flowers.

In contrast to weeks of tirades against its enemies, North Korean state media hardly made a mention of conflict.

The US has offered talks, but on the pre-condition that North Korea abandons its nuclear weapons ambitions.

North Korea deems its nuclear arms a "treasured sword" and has vowed never to give them up.

Nevertheless, US Secretary of State John Kerry, ending a trip to the region dominated by concern about North Korea, stressed his interest in a diplomatic solution.

"The United States remains open to authentic and credible negotiations on denuclearisation, but the burden is on Pyongyang," he said.

"North Korea must take meaningful steps to show that it will honour commitments it has already made, and it has to observe laws and the norms of international behaviour."

Yesterday evening, however, Mr Kerry appeared to open the door to talking without requiring the North to take denuclearisation steps in advance. China, he said, could be an intermediary.

Earlier, Mr Kerry said he believed China, the North's sole economic and political benefactor, should put "some teeth" in efforts to persuade Pyongyang to alter its policies.

The Chinese Communist Party mouthpiece, the People's Daily, warned today that tensions could get out of control.

"It does not matter if it is intentional or accidental, even the smallest thing could cause the situation to change rapidly and perhaps get totally out of control," the paper said.

South Korean and US officials said last week North Korea appeared set to test-launch a medium-range missile as a show of strength linked to today’s anniversary.

North Korea has conducted three nuclear tests, but it was not believed to be near weapons capability.

South Korea said it remained on guard against any missile launch and it regretted the North's rejection of an offer of talks made last week by President Park Geun-hye.

It said the offer would remain on the table.

Missile launches and nuclear tests by North Korea are both banned under UN Security Council resolutions, that were expanded after its third nuclear test, in February.