LONDON -- British police now say a total of roughly 21 people have sought treatment after a nerve agent was used to attack an ex-Russian spy and his daughter. Wiltshire acting police chief Kier Pritchard told Sky News on Thursday that "a number" of those people got blood tests, support and hospital advice.

He says only three people remain hospitalized. They are former Sergei Skripal, his daughter Yulia and police Sgt. Nick Bailey.

Officials say Bailey is making progress. The ex-spy and his daughter remain in critical condition.

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Police say the roughly 21 people treated include the three still hospitalized.