Chemical weapons experts in hazardous material protective suits have been deployed to five sites visited by Mr. Skripal and his daughter the previous Sunday: his home, the cemetery where his son and wife are buried, the restaurant, the pub and the bench where the two collapsed.

Around 180 military troops were called in to help clear the area, and the ambulance used to transport the two victims was wrapped in plastic and loaded onto a military transport vehicle.

Rebecca Hudson, a reporter for The Salisbury Journal, said on Sunday that local residents were beginning to complain that they had been kept in the dark about the risk level.

“I think people are frustrated that this information has come out seven days on, when they’ve been told throughout that there’s minimal risk,” she said by phone. “There is definitely the sense that they were not given enough information earlier in the week.”

In an editorial in the newspaper, Annie Riddle said that while there “wasn’t a hint of panic” during the first days of the investigation, residents have become progressively more concerned, as they have watched “more and more areas being taped off, barriers going up, more and more military and emergency services rushing about, and with nobody in authority saying a word.”

She added: “I find myself starting to wonder whether I’ve underestimated the potential danger. While no one expects any national security secrets to be given away, could we please be treated like grown-ups and be given a bit more idea exactly what is going on?”

Ruby Vitorino, 58, who works in a local jeweler’s shop, said many of her neighbors in “Smallsbury,” as she calls it, have responded with humor.