UK police: 21 people sought treatment after ex-spy poisoning

Only three people remain hospitalised after the poisoning Sunday in the southern English city of Salisbury, ex-spy Sergei Skripal, his daughter Yulia and a British police officer who tried to help them. Health officials insist there has only been a low risk to the public.

Authorities haven't said who launched the attack, but UK officials have warned of a strong response if the Russian government is found to be responsible.

"Multiple people have been treated, around 21 people, including the man and the woman found on the bench," Wiltshire acting police chief Kier Pritchard told Sky News, referring to Skripal and his daughter, who were found unconscious.

Pritchard said that of the new total, "a number" of them got hospital treatment including blood tests, support and advice. Previously, authorities had said only that "several" people had sought treatment.

Police haven't provided details on the nerve agent that was used, and the ex-spy and his daughter remain in critical condition.

British Home Secretary Amber Rudd said whoever is behind the attack is guilty of a "brazen and reckless act." She said Britain would respond strongly when it is clear who's to blame.

She said that enormous resources were being used to determine who poisoned Skripal, 66, and his 33-year-old daughter Yulia. They were found unconscious on a bench, triggering a police inquiry headed by counterterrorism detectives.

A police officer who came to their aid is hospitalised in a serious condition, though he is conscious and talking, Rudd said. He was identified today as Sgt. Nick Bailey.

"The use of a nerve agent on British soil is a brazen and reckless act," Rudd told Parliament. "This was attempted murder in the most cruel and public way."

The Russian Embassy in London, which has mocked other British politicians for suggesting Russian involvement, tweeted that it agreed with Rudd: "First evidence then conclusions on Mr. Skripal's case. Responsible political approach."

Police have refused to publicly speculate on who is behind the attack, but many experts have focused on Russia because of the similarity to the 2006 killing of another former Russian spy who was poisoned in London with radioactive polonium-210.

A public inquiry found that Russia was responsible for killing Alexander Litvinenko, and that President Vladimir Putin probably approved it.

The Russian government has denied any involvement in the Litvinenko killing or the attempted killing of Skripal, a former Russian agent who had served jail time in his homeland for spying for Britain before being freed in a spy swap.