South Korea is watching things in Beijing “very closely” — and keeping “all possibilities open” — following reports of a surprise visit by Kim Jong Un.

“Right now, the situation surrounding the Korean peninsula is moving very quickly and it would be inadvisable to think with prejudice,” explained a senior official in Seoul, who spoke to Reuters on Monday about the North Korean leader’s unconfirmed trip.

“The presidential Blue House is watching things in Beijing very closely, while keeping all possibilities open,” they said.

Kim is reportedly in the Chinese capital for what is believed to be his first foray outside North Korea since taking power in 2011 — and many believe it could be a sign of improving ties between the two nations.

“North Korea likely wants to confirm its relationship with China and believes it has some leverage with which it can ask for things from China,” explained Yoo Ho-yeol, professor of North Korean studies at Korea University in Seoul.

“If North Korea speaks with the United States on its own, it might feel it is at a disadvantage,” he said. “But, if it has China as an ally, Pyongyang may think it will be able to protect its interests and profits during the summits.”

While it’s unclear why Kim is in Beijing, sources told Japan’s Kyodo News that it was intended to improve relations following China’s backing of economic sanctions on the rogue nation.

The Blue House official whom Reuters spoke to said the South Koreans knew of “related movements” in North Korea — including a reported train ride Kim took to get to the Chinese capital — but he was unable to confirm whether Kim was actually involved.

“We are closely monitoring the situation and trying to gather further information through various channels,” the Blue House said in a statement Monday following Bloomberg’s report about Kim’s visit.

It’s unclear how long the young leader will be in Beijing. He’s slated to hold summits with South Korea in late April and the US in May.

“The fact that the summits are being held has been beyond our expectations,” the Blue House official told Reuters.

With Post wires