Sajid Javid has said “the risk to the public remains low” following the nerve agent poisonings in Wiltshire.
Speaking on a visit to Amesbury where two people remain critically ill in hospital, the home secretary said he was “very confident” police would uncover the source of the Novichok.
The couple’s symptoms were the same as those of Sergei and Yulia Skripal, who were poisoned in March.
Mr Javid praised emergency services for their response to the poisonings.
On his first visit as home secretary to Salisbury and Amesbury, where Dawn Sturgess, 44, and her partner Charlie Rowley, 45, fell ill a week ago, he met local people and business owners.
Police believe the couple handled an item contaminated with the nerve agent Novichok.
Amber Rudd, Mr Javid’s predecessor who resigned in April, had previously visited the site in Salisbury where Russian ex-spy Mr Skripal and his daughter were poisoned with Novichok.
Mr Javid said government experts had determined the original attack was a “barbaric, inhuman act by the Russian state.” Russia has denied any involvement.
Mr Javid said the area remains “open for business” and urged people to show their support and visit.
He said: “I want to take the opportunity to say to everyone, but especially local people, that the risk to the public remains low.”
The police’s “working hypothesis” is that the Amesbury poisoning and the Salisbury incident are linked, the home secretary said, but he called for the police to be given “time and space” to work.
“What I am very confident of, with the amount of police work that’s going on here, the support both from Wiltshire Police but also more than 100 officers from the counter-terrorism network involved as well, that they will eventually, one way or the other, get to the bottom of this,” he said.
‘Need to learn more’
Mr Javid said there were “no plans” for further sanctions against Russia, but he repeated the government’s assessment that Russia was the source of the Novichok.
“What our expert scientists have determined is that the nerve agent in this incident is the same exact nerve agent that was used back in March,” he said. “We know back in March that was the Russians, it was a barbaric, inhuman act by the Russian state.
“Again for this particular incident we need to learn more and let the police do their work.”
He rejected suggestions that the government had been too quick to insist Salisbury was safe after the attack on the Skripals in March.
It is not believed that the couple in the latest poisoning incident had visited the sites connected to the Skripals in Salisbury, he said.