A British scientist who studied the Chernobyl disaster in the former Soviet Union has been mysteriously deported from Belarus while on a lecture tour.
Chernobyl was the world's worst nuclear disaster
The decision to rescind his visa was made by the former Soviet republic's interior ministry.
Dr Alan Flowers, a specialist in radiology based at Kingston University, said he was being removed because of his contact with non-government groups.
The Foreign Office confirmed the deportation but declined to comment.
Dr Flowers reportedly started studying the effects of the disaster in 1992.
The Chernobyl power station, in Belarus' neighbouring former Soviet republic Ukraine, exploded on 26 April 1986.
The blast, which killed at least 30 people and forced the evacuation of 135,000 more people because of the level of nuclear contamination in the area, was the world's worst nuclear disaster.
Vladimir Kuzura, an official from the Belarusian Interior Ministry, refused to explain the reasons behind the withdrawal of Dr Flowers' visa and the deportation order.
But Dr Flowers is said to have made a claim that, if proved right, would cause great embarrassment to former top Soviet officials.
According to Vera Rich, who was the Soviet correspondent of the scientific journal Nature at the time of the tragedy, many believe the then Soviet Union seeded clouds to make them rain on Belarus.
Freedom of speech
The move was aimed at preventing winds from blowing contaminated material towards Moscow, theorists say.
But many scientists are highly dubious of claims for successful cloud-seeding. One of the problems is proving that any rain following experiments would not have fallen anyway.
According to Ms Rich, who is currently a freelance writer for the Ukrainian Weekly, Dr Flowers said he had many colleagues in Belarus who believe in this theory but would never admit it in public for fear of retaliation.
In her article, she quoted him as saying: "For a full understanding of the distribution and effects of the Chernobyl fallout, we need as much evidence as possible.
"What caused the rain is still an uncertainty in our knowledge about the intensity and nature of the contamination."
The Chernobyl disaster led to a dramatic rise in the number of cases of thyroid cancer, leukaemia and birth defects, especially in Belarus.
Up to seven million people are believed to have been affected.
Belarusian President Alexander Lukashenko has imposed strict controls on freedom of expression, and the country is being increasingly isolated by the west.