An Air France plane that was to have repatriated French citizens from the Republic of Congo back to Paris amid the coronavirus epidemic was damaged by gunfire while on the airport tarmac, the airline and sources said Sunday.

The incident took place at the airport of Pointe-Noire, a port city and the Republic of Congo's main oil hub. No crew or passengers were onboard at the time.

"Air France confirms that during the night of April 11th, an Airbus A330 belonging to the airline was damaged due to an incident on the tarmac of Pointe Noire's airport," the company said in a statement.

The flight to Paris -- via Bangui in the Central African Republic -- had been planned for Sunday and it has now been delayed for 24 hours to obtain a replacement aircraft, it added.

A source close to the issue told AFP that the aircraft had been hit by gunfire, without giving further details.

From the capital Brazzaville, Foreign Minister Jean-Claude Gackosso sent his "deepest regrets" to French counterpart Jean-Yves Le Drian after this "serious incident".

The minister also spoke to French ambassador Francois Barateau to apologise for the incident, the envoy said.

A source close to the issue, who asked not to be named, said it appeared the incident was due to a disagreement between a member of the local security forces and his boss.

"The person who fired the shot was under the influence of alcohol. It was a Kalashnikov shot that hit the plane," said the source.