A Moscow court has cleared the way for the families of thousands of Polish army officers massacred by the Soviet Union in 1940 to have their cases heard.
A lawyer representing the families say they want to prove the officers were victims of Soviet repression and not criminals.
Tuesday's Moscow court decision overturned a lower court ruling rejecting the case.
More than 22,000 Polish army officers and other Poles who opposed the Soviet invasion of Poland were rounded up and massacred in the forests outside Katyn in western Russia and other sites in 1940.
Their bodies were tossed into mass graves.
Soviet authorities blamed the Nazis who occupied parts of Russia and Ukraine for the massacre until 1990, when Soviet leader Mikhail Gorbachev admitted Soviet responsibility.
Some information for this report was provided by AFP and Reuters.