American authorities reportedly refused an Air France flight from Paris to Mexico entry into US airspace because a left-wing journalist writing a book on the CIA was on board.

Hernando Calvo Ospina, who works for Le Monde Diplomatique and has written on revolutionary movements in Cuba and Colombia , figured on the US authorities’ "no-fly list".

Air France said the April 18 flight was forced to divert to the French Caribbean island of Martinique before continuing its journey and that it might ask the US Transportation Security Administration for compensation.

A spokesman for Mr Ospina’s French publisher, Le Temps des Cerises, said: "Hernando, who was heading to Nicaragua to research a report, thus found out that he is on a ’no-fly list’ that bans a number of people from flying to or even over the United States." Some 50,000 people are said to be on the list set up under George W. Bush, the former US president.

The publisher accused the Central Intelligence Agency of being behind Mr Ospina’s blacklisting, pointing out that the journalist was currently researching a book about the spy agency. "It shows to what degree its paranoia (has reached)," it said.

Air France said that as the flight was not due to stop in a US airport, it had not sent US authorities the passenger manifest. However, it sent one to Mexico, which apparently sent the list on. The crew were informed of the ban as they approached US airspace.

Mr Ospina, who has written several books and contributes to Le Monde Diplomatique, the left-wing French political monthly, said that he was informed of the order to divert the flight by its co-pilot.

"I was speechless and my first reaction was to ask, ’Do you think I’m a terrorist?’," he said. "He replied ’no’ and said that was why he told me about it, adding that it was extraordinary and the first time it had happened on an Air France plane."

Maurice Lemoine, editor in chief of Le Monde diplomatique, said: "Hernando Calvo Ospina is a Colombian political exile in France who writes a lot denouncing the government of (President) Alvaro Uribe and the role of the United States in Latin America, and as a journalist has had occasion to interview top members of the Farc (leftist guerillas in Colombia). That seems enough for him to be considered a terrorist."

Since the Sept 11, 2001 attacks, American officials have maintained a secret "terrorist watch list" of individuals forbidden to fly into or out of the US because they are thought to pose a security threat.

Critics claim that, instead of simply targeting known extremists who pose a potential danger in the "war against terror", it has been abusively extended to peaceful critics of US policy. People with similar names to suspected militants have also been listed.