UK to Expel 23 Russian Diplomats over Spy poisoning

Russia responded on Wednesday by calling London's move "an unprecedentedly crude provocation".

Theresa May, the UK prime minister, said Moscow reacted with "complete disdain" to a deadline issued on Monday for it to provide an explanation on how a Russia-made nerve agent ended up in Salisbury, in southern England, where the attack occurred.

Skripal, 66, and his daughter Yulia, 33, were found unconscious on a bench outside a shopping center in Salisbury on March 4, after they were poisoned. The two remain in critical condition in a hospital, Al Jazeera reported.

A former double agent, Skripal betrayed dozens of Russian agents to British intelligence before his arrest in Moscow in 2004. He was later sent to the UK in exchange for captured Russian spies.