U.K. police say 21 people sought treatment after poisoning of former spy

LONDON—Around 21 people have received medical treatment after a nerve-agent attack on an ex-Russian spy, British police said Thursday, as the U.K. vowed strong action against whoever was responsible for the “brazen and reckless” act.

Three people remain hospitalized after the poisoning Sunday in the southern English city of Salisbury — former spy Sergei Skripal, his daughter and a British police officer who tried to help them.

Health authorities say there is little risk to the wider public. But Wiltshire county acting police chief Kier Pritchard said “around 21 people” have had treatment, including the Skripals, who were found unconscious on a bench.

Pritchard said “a number” of the 21 were having “blood-tests, support and advice.” Previously, authorities had said only that “several” people had sought treatment.

The ex-spy and his daughter remain in critical condition in a Salisbury hospital. A police officer who came to their aid, Sgt. Nick Bailey, is hospitalized in a serious condition, though he is conscious and talking, officials said.

British Home Secretary Amber Rudd said enormous resources are being devoted to determining 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.

“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.”