The Vatican on Friday reported its first coronavirus case and closed some offices to protect hundreds of the micro-state's priests and residents from the virus raging in surrounding Italy.
The confirmed case prompted a sympathetic message from the pope and redoubled the fears of tourists who have all but emptied Saint Peter's Square.
The Holy See's spokesman Matteo Bruni told AFP that the patient had tested positive on Thursday for COVID-19 at the Vatican health clinic.
The Vatican later said the person had participated at an international conference organised by the Holy See on artificial intelligence that was attended by Microsoft President Brad Smith.
It said Smith and other participants of the February 26-28 event had been notified as a precaution.
The Pope himself missed the conference because he has been out of action for over a week with a cold.
Some offices of the Secretariate of State -- the Vatican's central government -- were also closed Friday as a precaution following another suspected case of COVID-19.
A source at the Vatican said officials were awaiting that test's results but gave no details.
Pope Francis told his 18.1 million Twitter followers that he wished to "express again my closeness to those who are ill with the coronavirus and to healthcare workers who are caring for them".
The Vatican and its 450 residents are entirely surrounded by Italy.
The Mediterranean country of 60 million is battling the most deadly virus outbreak outside China -- 197 people have died in the past two weeks and 4,636 people have been infected.
- 'Many cases, many deaths' -
The few tourists strolling around the normally crowded Saint Peter's Square on Friday sounded anxious about the rapid spread of the new disease.
"I am afraid because it is a new thing. There are many cases, many deaths," 41-year-old Brazilian nun Lucilia said at the Vatican.
"Everything is happening very quickly and we are scared because we are sure of nothing."
Pope Francis has recently suffered from a bad cold but reportedly tested negative for COVID-19.
The 83-year old has a personal doctor and does not visit the medical centre -- except for rare trips to greet staff.
- 'Avoid dissemination' -
The Vatican said on Thursday it was considering changes to Pope Francis's schedule "to avoid the dissemination" of the new coronavirus.
It did not say whether the Argentinian pontiff would be temporarily kept away from crowds or whether he would stop shaking hands with visitors.
Francis has not been seen in public since announcing during his traditional Sunday prayer before crowds in Saint Peter's Square that he was skipping an annual spiritual refuge south of Rome because of a cold.
The pontiff has cut down his schedule and has spent most of his time at home, the Saint Martha's guest house in the Vatican.
"The cold with which the Holy Father was diagnosed is running its due course," Bruni told journalists Thursday.
Francis lost part of a lung as a young man and suffers from sciatica.
But he rarely cancels appointments and normally takes extra time to mingle with crowds.
The Vatican is expected to supply staff working in close contact with tourists with masks and gloves.