LONDON — A British police official on Thursday updated the number of people who sought treatment after a nerve agent attack on a former Russian spy, saying ‘‘around 21’’ had been given medical help and support.
Three people remain hospitalized after the poisoning Sunday in the southern English city of Salisbury: former spy Sergei Skripal, his daughter Yulia, and a British police officer who tried to help them. Health officials insist there has been only 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. The two remain in critical condition.
Previously, authorities had said only that ‘‘several’’ people had sought treatment.
Police haven’t provided details on the nerve agent that was used.
British Home Secretary Amber Rudd said that 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.