Pope Francis on Thursday received an invitation to visit North Korea and the pontiff indicated he would consider making what would be a landmark trip to a nation known for severe restrictions on religious practice, according to South Korean officials.

South Korean President Moon Jae-in relayed the invitation from North Korean leader Kim Jong Un to the pope verbally during a 35-minute meeting in the Vatican.

Any visit would be the first by a pope to the reclusive state which does not allow priests to be permanently stationed there. There is little information on how many of its citizens are Catholic, or how they practice their faith.

North Korea's constitution guarantees freedom of religion as long as it does not undermine the state.

But beyond a handful of state-controlled places of worship - including a Catholic church in the capital of Pyongyang - no open religious activity is allowed and the authorities have repeatedly jailed foreign missionaries.

Kim told Moon, a Catholic, of his wish to meet the pontiff during a meeting last month and the South Korean leader announced before the trip that he would be relaying a message.

According to the president's office, Francis expressed his strong support for efforts to bring peace to the Korean peninsula. Moon's office quoted the pope as telling Moon: "Do not stop, move forward. Do not be afraid."

Asked if Kim should send a formal invitation, Moon's office quoted the pope as responding to Moon: "your message is already sufficient but it would be good for him to send a formal invitation."

"I will definitely answer if I get the invitation, and I can go," the president's office quoted the pope as saying.