The Kremlin says Russia is not investigating the two men that Britain has named as suspects in the nerve agent attack on a Russian ex-spy.
Britain on Wednesday announced charges in absentia against two alleged Russian agents, Alexander Petrov and Ruslan Boshirov.
British Prime Minister Theresa May has accused the Russian government of orchestrating the March attack on ex-Russian spy Sergei Skripal and his daughter Yulia in the English city of Salisbury.
The Skripals became gravely ill but survived.
Dmitry Peskov, spokesman for President Vladimir Putin, said on Thursday that May's accusations were "unacceptable" and that "no one in the Russian leadership" had anything to do with the poisoning.
Peskov said Russia "has no reasons" to investigate the two individuals charged on Wednesday because Britain has not asked for legal assistance on the case.
Britain's security minister, meanwhile, says Russian President Vladimir Putin bears ultimate responsibility for the Novichok nerve agent attack.
Ben Wallace told the BBC on Thursday that Putin and his government "controls, funds and directs the military intelligence" unit known as the GRU that Britain believes used Novichok to try to kill ex-Russian spy Sergei Skripal and his daughter Yulia.
Britain plans to press its case against Russia in the UN Security Council on Thursday. Many Western countries have already imposed sanctions on Russia because of the attack.
Walls said the GRU is directly linked to Russia's Defence Ministry, the Kremlin and Putin's office.
