A high-ranking North Korean official, possibly leader Kim Jong-un, is thought to have visited the northeastern Chinese city of Dalian ahead of the U.S.-North Korea summit. 

A source familiar with North Korea affairs told KBS that Dalian Airport was closed off to the public from 8 a.m. to 1 p.m. on Monday and roads around the Bangchuidao Guesthouse in the city were also closed on Monday afternoon. 

The source said that it is possible the Chinese government invited a ranking North Korean official ahead of the first sea trial of China's first domestically built aircraft carrier, the Type 001A, which local media reported would begin Tuesday morning. 

There is speculation that Kim could be visiting the city to meet with Chinese President Xi Jinping. 

The airport is again scheduled to be closed off to the public Tuesday afternoon, raising rumors that Kim is set to depart after meeting with Xi. 

If the two officials met, it would have been their second meeting in some 40 days after Kim's surprise visit to Beijing in late March. 

The presidential office says it is "closely watching" news reports regarding the speculation.

Asked about the rumors, a senior presidential official said Tuesday that he can't talk about specifics, but didn't deny that a meeting between North Korean and Chinese officials could be taking place. 

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