A A man cries in front of a memorial dedicated to firefighters who died after the Chernobyl nuclear disaster, during a night service near the Chernobyl plant in the city of Slavutych, Ukraine April 26, 2006. [Reuters]

"We are playing for the dead," said Bruno Boussagol, the producer and artistic director of the Brut de Beton troupe.

Some five million people are believed to have been affected by the disaster in Belarus, Russia and Ukraine, all of which still have regions where the levels of dangerous cesium-137 and strontium-90 radioisotopes are much higher than accepted norms.

Two decades on, millions of acres (hectares) of agricultural and forest land remain contaminated from the accident and its death toll is hotly debated.

Agencies of the United Nations, backed by the governments of Belarus, Russia and Ukraine, estimate that between 4,000 and 9,000 people could be expected to die overall as a direct consequence of the accident.

Environmental groups put the figure at 100,000 and higher.

The UN has estimated that the disaster will end up costing hundreds of billions of dollars.

The Chernobyl plant was eventually closed for good in December 2000 but will continue to be a concern for years to come.

The concrete sarcophagus that was hastily constructed over its destroyed reactor immediately following the accident is showing signs of wear and more than 20 countries have chipped in nearly a billion dollars for the construction of a 20,000-ton steel case to take its place.

Construction of the new containment unit is expected to begin later this year and Ukraine hopes to complete it by 2010.