British police said Thursday that a couple left critically ill in the same area where a former Russian spy was poisoned earlier this year "handled a contaminated item."
The police said in a statement that tests of samples from Dawn Sturgess, 44, and Charlie Rowley, 45, showed they were exposed to the nerve agent Novichok and now are trying to determine the source of the contamination.
Novichok is a Soviet-designed nerve agent that is believed to be more potent than such better known toxins as VX and sarin.
WATCH: Britain, Russia Clash Over New Nerve-Agent Poisoning Case
Britain's interior minister, Sajid Javid, said the toxin that sickened the couple "has been identified as the same nerve agent that contaminated" former Russian double agent Sergei Skripal and his daughter Yulia. Javid said it is not clear whether the nerve agent that poisoned the British couple is from the exact same batch used in the attack on the Skripals.
The couple was found unconscious Saturday in Amesbury, 13 kilometers from Salisbury, where Sergei and Yulia Skripal were found in March.
Security Minister Ben Wallace told the BBC on Thursday investigators believe the new exposure is a result of the March incident and not a new attack directed at Sturgess and Rowley.
The unexpected poisoning of the couple, with no known link to Russia, has raised public concerns in the Salisbury area. Health officials say the risk to the public is low.
Britain has blamed Russia for poisoning the Skripals with Novichok, a nerve agent developed by the Soviet Union during the Cold War.
Wallace called on Russia to share information about the poisoning.
Russia has denied any involvement and instead has claimed that Britain itself was to blame for the attack, in an attempt to stoke anti-Russian sentiments.
Russian Foreign Ministry spokeswoman Maria Zakharova called on British law enforcement authorities at a briefing Thursday "not to get involved in dirty political games" that "Theresa May's government has stirred up" and demanded an apology from Britain.
Earlier Thursday, Kremlin spokesman Dmitry Peskov said "the British government has not presented any evidence of Russia's involvement in this, besides unfounded accusations."
The Kremlin also said Thursday it had offered to help Britain with the Skripal investigation, but that Britain had declined.
The incident prompted the biggest expulsion of Russian diplomats since the Cold war as the United States and Britain's European allies sided with London in blaming Moscow.