The UK's interior minister has called a nerve agent attack on a Russian ex-spy a cruel and public attempt at murder.

66-year-old former double agent Sergei Skripal and his 33-year-old daughter remain in critical condition. They were found unconscious outside a shopping centre in the southern English city of Salibury on Sunday, several kilometers from Britain's chemical and biological warfare research facility. The UK says it'll strongly pursue those responsible and is committed to bring the suspects to justice.