Pilgrims on the Vatican's new chartered airline have been told to leave holy water behind for security reasons.
Passengers can not carry liquids in containers of more than 100 ml
Officials at Tarbes-Lourdes airport in southern France said that bottles of water from the shrine at Lourdes could present a potential terrorist threat.
The pilgrims were told they could not carry holy water in bottles bigger than the maximum allowed: 100 ml.
Security staff at the airport said they were simply following international anti-terror regulations.
Measures limiting liquids allowed in carry-on baggage came in response to claims by British police in 2006 that there was a plot to bring down US-bound flights using liquid explosives.
Francesco Pizzo, Mistral Air's president, said the company had to respect international regulations on the matter.
The airline provided a small bottle of holy water, in the shape of the Virgin Mary, for each passenger, once they had boarded the plane for the flight home from Lourdes.
Mistral Air began flights from Rome to Lourdes on Monday and plans to extend its service to other Roman Catholic shrines.