Pope Francis is considering an unprecedented visit to North Korea, according to a Vatican official. An invitation from Kim Jong Un was relayed to the Pope by South Korea President Moon Jae-in during a meeting in the Vatican on October 18.

It would be the first visit by a Pope to the reclusive East Asian state, which is known for severe restrictions on religious practice and does not allow priests to be permanently stationed there.

Vatican secretary of state Cardinal Pietro Parolin said the Pope was considering the visit. He told reporters: “The Pope expressed his willingness. We have to wait for it [the invitation] to be formalized.”

Cardinal Parolin said North Korea would have to meet certain conditions ahead of any potential visit by the Pope.

“This will come later,” he added. “Once we start thinking in earnest about the possibility of making this trip, then we will have to think about conditions in which the trip can take place. “[The Pope] is willing to make the trip, but a trip of this kind will need serious preparation.”

Beyond a small number of state-controlled places of worship, including a Catholic Church in the capital of Pyongyang, no open religious activity is allowed in North Korea. Authorities have repeatedly jailed foreign missionaries.