Beijing/Seoul: North Korean leader Kim Jong Un has pledged to denuclearise and meet US officials, China said on Wednesday after an historic meeting with President Xi Jinping, who promised China would uphold its friendship with its isolated neighbour.

After two days of speculation, China and North Korea both confirmed that Kim had visited Beijing and met Xi during what China’s Foreign Ministry called an unofficial visit to China from Sunday to Wednesday.

The China visit was Kim’s first known trip outside North Korea since he assumed power in 2011 and is believed by analysts to serve as preparation for upcoming summits with South Korea and the United States.

North Korea’s KCNA news agency made no mention of Kim’s pledge to denuclearise, or his anticipated meeting with US President Donald Trump that is planned for some time in May.

Beijing has traditionally been the closest ally of secretive North Korea, but ties have been frayed by North Korea’s pursuit of nuclear weapons and China’s backing of tough U.N. sanctions in response.

China’s Foreign Ministry cited Kim in a lengthy statement as telling Xi that the situation on the Korean peninsula is starting to improve because North Korea has taken the initiative to ease tensions and put forward proposals for peace talks.

‘It is our consistent stand to be committed to denuclearisation on the peninsula, in accordance with the will of late President Kim Il Sung and late General Secretary Kim Jong Il,’ Kim Jong Un said, according to the statement.

North Korea is willing to talk with the United States and hold a summit between the two countries, he said.

‘The issue of denuclearisation of the Korean Peninsula can be resolved, if South Korea and the United States respond to our efforts with goodwill, create an atmosphere of peace and stability while taking progressive and synchronous measures for the realisation of peace,’ Kim said.

Kim Jong Un’s predecessors, grandfather Kim Il Sung and father Kim Jong Il, both publicly promised not to pursue nuclear weapons but secretly continued to develop the programmes, culminating in the North’s first nuclear test in 2006 under Kim Jong Il.

The North had said in past failed talks aimed at dismantling its nuclear programme that it could consider giving up its arsenal if the United States removed its troops from South Korea and withdrew its so-called nuclear umbrella of deterrence from South Korea and Japan.

Many analysts and former negotiators believe this still constitutes North Korea’s stance on denuclearisation of the Korean peninsula and remain deeply sceptical Kim is willing to give up the nuclear weapons his family has been developing for decades.