Russia on Tuesday opened a probe into "financing terrorism" that implicates Western countries, saying funds received by US firms in Ukraine -- including one that employed Joe Biden's son -- were used for "terrorism acts" in Russia.
The announcement came with Moscow continuing to blame the West and Ukraine for the attack on a concert hall last month that left 144 dead.
The attack on the Crocus City Hall has been claimed by the Islamic State group and US officials have said they warned Moscow of an imminent attack.
Moscow's Investigative Committee said it was "investigating the sources of income" worth millions of dollars and the "involvement of specific individuals from government officials and public commercial organisations of Western countries".
It cited the name of a company that employed Hunter Biden, the US president's son.
