Kim Jong-un Returns After Beijing Talks: Media

North Korean leader Kim Jong-un has left for Pyongyang later in the day after making his third visit to China this year, according to the state media reported, underscoring the major improvement in relations between the communist neighbours.

Xinhua said Kim met President Xi Jinping for a second day of talks on Wednesday and cited Kim as saying the visit was an opportunity to "deepen the friendship" between the two leaders and advance bilateral ties.

Kim earlier visited an agricultural technology park and rail traffic control centre, accompanied by Beijing's top official, Cai Qi, Xinhua said.

Kim's motorcade was seen leaving the North Korean Embassy on Wednesday afternoon as police closed off major roads and intersections in central Beijing.

Gawking pedestrians watched the passing motorcade that included Kim's limousine – a black Mercedes-Benz Maybach with gold emblems on the rear doors – as well as several minibuses and 15 motorcycle police clad in white suits.

The motorcade travelled to Beijing's airport, where the limousine entered the charter flight terminal.

In Seoul, South Korean President Moon Jae-in urged North Korea to present actionable plans on how it will scrap its nuclear programme, and for the United States to swiftly take unspecified corresponding measures.

"It's necessary for North Korea to present far more concrete denuclearisation plans, and I think it's necessary for the United States to swiftly reciprocate by coming up with comprehensive measures," Moon said.

Moon's office said he made the remarks to Russian media ahead of his trip to Moscow later this week. (AFP)