Kremlin says Britain must prove Russia’s involvement in the poisoning of former double Agent Sergei Skripal in the UK or apologize.

Presidential spokesman Dmitry Peskov said sooner or later these unsubstantiated allegations will have to be answered for.

Russian President Putin on Sunday rejected as “Nonsense” allegations by London and its allies that Moscow was behind the March 4 attack on Sergei Skripal and his daughter Yulia in the English city of Salisbury.

In response British Foreign Secretary Boris Johnson said Moscow’s denials were becoming “increasingly absurd”.