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.

"It has been established that financial funds received through commercial organisations, including the oil and gas company Burisma Holding, working in Ukraine over recent years were used to carry out terrorist acts inside Russia," the committee said. 

It said the investigation was working to establish "links of the direct perpetrators of terrorist acts with their foreign curators, organisations and sponsors". 

The move comes as US Republicans are trying to inflict damage on the Democratic president, accusing him of using his influence to help his son in his business dealings in Ukraine. 

Joe and Hunter Biden claim that they did not do anything illegal. 

In February, a former FBI informer was arrested for having fabricated corruption accusations against the Bidens.