North Korean leader Kim Jong Un listens to US President Donald Trump during a meeting on Sentosa Island in Singapore last week. File picture: Evan Vucci/AP

Beijing - North Korean leader Kim Jong Un is visiting China on Tuesday and Wednesday, China's state-run Xinhua news agency reported.

Japan's Kyodo news agency reported that a North Korean plane thought to be carrying a high-ranking official arrived at Beijing International Airport on Tuesday.

Kim is expected to brief Chinese President Xi Jinping on the historic summit held between the North Korean leader and US President Donald Trump last week in Singapore.

This is Kim's third visit to China, after meeting with Xi in March in Beijing and again in May in the north-eastern Chinese city of Dalian.

Meanwhile, the US and South Korea suspended planning for joint military exercises scheduled for August, the Pentagon said late Monday, following a promise made by Trump at the summit.

The motorcade which is believed to be carrying North Korea leader Kim Jong Un passes by policemen as it leaves the Beijing Capital International Airport. Picture: Andy Wong/AP

"Consistent with President Trump's commitment and in concert with our Republic of Korea ally, the United States military has suspended all planning for this August's defensive wargame Freedom Guardian," spokeswoman Dana W White said.

"We are still coordinating additional actions. No decisions on subsequent wargames have been made," she said.

Trump apparently surprised his Asian ally South Korea as well as the US military when he announced the cancellation of joint military exercises last week following his meeting with Kim in Singapore.

The limousine of North Korean Leader Kim Jong Un is seen on the road at Singapore's Changi Airport. Picture: Joseph Nair/AP

China, which is North Korea's main ally and trading partner, applauded the decision.

Nevertheless, Beijing said it supported Washington's decision to not lift sanctions against North Korea until the state completely denuclearizes.

US Secretary of State Mike Pompeo said Thursday in Beijing that sanctions against Pyongyang will not be lifted until it denuclearizes in a way that is "complete, verifiable and irreversible."