By Yi Whan-woo

China is beefing up its patrols on its border with North Korea, fueling speculation that Chinese President Xi Jinping may visit Pyongyang for North Korea's founding anniversary on Sept. 9.

"Such tighter patrols usually come when top Chinese or North Korean officials visit each other's country," a source familiar with Pyongyang said last week. "Kim already visited China this year and it may be Xi who will be crossing the border for the celebration of North Korea's anniversary."

A China-based tourism agency, INDPRK, also said it would stop all group travel packages to North Korea from this week until Sept. 5.

The agency said this was because all hotels in Pyongyang had been undergoing renovation since Aug. 11 and therefore a shortage of rooms.

But sources said stopping group travel packages suddenly may be linked to Xi's potential visit to Pyongyang.

North Korea cited different reasons in the past when it prepared for significant events and restricted entry of foreigners.

"It is believed that North Korea is preparing for an important event, or high-ranking officials are planning a visit, considering that Pyongyang is restricting entry of foreigners over the peak tourism season, even though it is one of its main sources of profit," a source said.

Another source said, "It is hard to understand why North Korea would suspend its tourism business just to renovate hotels, when the industry has been raking in money."

Kim and Xi have met in China three times since March and it there was speculation that Xi might make a reciprocal visit within this year.