BERLIN (Reuters) - German police said they are investigating the possible poisoning of two Russian exiles who attended a conference in Berlin at the end of April, organised by Russian Kremlin critic Mikhail Khodorkovsky.

Berlin police told Reuters "a file had been opened" after German newspaper Welt am Sonntag, citing Russian investigative media group Agentstvo, said two women reported symptoms that suggested possible poisoning.

Police gave no further details.

(Reporting by Maria Martinez; Editing by Alexandra Hudson)