A person who appears to be a high-ranking North Korean official arrived at Beijing International Airport and went downtown by car on Monday, a source close to the matter said.

The car was one that China usually uses for state guests, the source added. At the airport, an official of China's ruling Communist Party and North Korea's ambassador to China greeted the delegation led by the high-ranking official, the source said.

It was not immediately clear who is visiting China from North Korea. But taken together, the developments indicate that high-ranking officials of the two countries may meet or may have met to exchange views on issues such as denuclearization and economic aid ahead of a U.S.-North Korea summit on June 12 in Singapore.

Relations between Beijing and Pyongyang have been drastically improving in recent months, with North Korean leader Kim Jong Un having visited China and held talks with President Xi Jinping in March and May.

Earlier this month, Chinese Foreign Minister Wang Yi visited Pyongyang, a move seen to suggest the two countries are trying to promote exchanges of high-raking officials.

In late March, Kim travelled to Beijing on his first foreign trip since becoming North Korea's supreme leader following the death of his father Kim Jong Il in December 2011.

China, North Korea's main economic lifeline, had been increasing economic sanctions against Pyongyang since late last year as Kim continued to develop ballistic missiles and nuclear weapons in defiance of international warnings, leading to a deterioration in bilateral ties.

==Kyodo