Four men have been charged with carrying out an attack at a concert in Moscow on Friday that killed more than 130 people. They all appeared in court on Monday heavily bruised with swollen faces and black eyes – with one attending in a wheelchair wearing a hospital gown.  The Islamic State group said it carried out the attack on the Crocus City Hall, but President Putin has insisted Ukraine was involved. President Zelenskyy has strongly denied the claims and hit out at the Russian leader and others in Moscow, describing them as “scum”.   Questions are now mounting for President Putin as it emerged the US government warned Russia two weeks ago that an attack by extremists on “large gatherings including concerts” was imminent.  On this edition of the Sky News Daily, Leah Boleto is joined by international affairs editor Dominic Waghorn and international correspondent in Moscow Diana Magnay to discuss the mood in the Russian capital and how President Putin could react.Producer: Alex Edden Assistant producer: Iona Brunker  Editor: Paul Stanworth