The relatives of Russian businessman Boris Berezovsky, who died in the UK on Saturday, have still not decided on the possible place of his burial, but are confident that he died of natural causes, a source close to the businessman's family told Interfax on Sunday.

"We can now say with 100% certainty that the cause of death was natural," a source told Interfax, citing Berezovsky's relatives.

"The place of his possible burial has not bee discussed yet. The family doesn't even know yet when the investigative actions will be completed, when the final death certificate will be issued, and when the body will be given to the relatives," the source said.

Speaking about when the body will likely be handed over to the relatives, the source recalled that the investigative actions following the death of Berezovsky's business partner Badri Patarkatsishvili took some two weeks.

When asked whether the relatives will ask for Berezovsky to be buried in Russia, the source said: "I think there is little probability of that because many of Berezovsky's friends were unable to attend the funeral for various reasons. Although it would be great if Berezovsky was buried in Russia."

Berezovsky immigrated to the UK in 2000. In Russia, the businessman was charged with many crimes and was sentenced to a prison term in absentia.

The businessman's son-in-law Yegor Shuppe reported on Berezovsky's death on Facebook on Saturday.