A British coroner will consider a government request to keep some evidence secret during the upcoming inquest into the death of Aleksandr Litvinenko.
The dissident and former Russian security agent died of polonium poisoning in 2006 in London.
The request is being opposed by several media groups, including the BBC, "The Independent," and "The Guardian."
"The Independent" reports that confirmation and details of Litvinenko's suspected collaboration with British intelligence services are likely to be among the evidence the government wants withheld.
Britain's Foreign Office argues secrecy is needed to protect the country's international interests.
The inquest starts in May, and will look into claims that two Russian citizens, Andrei Lugovoi and Dmitry Kovtun, were part of a Kremlin plot to kill Litvinenko.
Moscow has refused British requests to extradite the two for questioning.
Based on reporting by BBC and "The Independent"