Ten people have been arrested in Russia over the murder of investigative journalist Anna Politkovskaya.Russian TV showed prosecutor general Yuri Chaika telling President Putin of the arrests, informing him that those held would soon be charged.Mr Chaika said "serious progress" had been made in the investigation into the killing, which was widely condemned.The journalist, a harsh critic of President Vladimir Putin, was shot dead at her Moscow apartment block in 2006.At the moment there is no information about the identity of the suspects.