British police said Wednesday that two people found unconscious over the weekend were poisoned by Novichok, the same nerve agent used against Russian ex-spy Sergei Skripal and his daughter. The two new victims, a man and a woman, were found Saturday in Amesbury, which is located about eight miles away from Salisbury, where Skripal and his daughter were stricken in March.

The two new victims, identified by British media as Dawn Sturgess and Charlie Rowley, both in their mid-40s, remained hospitalized on Thursday morning in critical condition.

Police said it is unclear if this incident is linked to the earlier poisoning of Sergei and Yulia Skripal, or if the batch was the same as the one that poisoned them on March 4.

Police say no on else has presented with the same symptoms, according to BBC News. Medical officials said Wednesday people who had been in the area where the couple had been should take precautions and wash their clothes. They stressed, however, that given only two people appeared to be affected, there was not deemed to be a health risk to the wider public.

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Counterterrorism police detective Neil Basu said it was unclear if the couple were targeted or if the poisoning was accidental. There was "nothing in their background" to suggest the pair were targeted, police said.

Images from Facebook show Dawn Sturgess, 44, and Charlie Rowley, 45, identified British media as the couple who fell ill after coming into contact with Novichok nerve agent in Amesbury or nearby Salisbury, England on June 30, 2018. FACEBOOK

Counterterrorism officials are now leading the investigation, according to BBC News.

Novichok is a nerve agent developed in the Soviet Union near the end of the Cold War. British Prime Minister Theresa May said in March this indicated it was "highly likely" Russia was behind the attack on the Skripals.

That poisoning led to international condemnation and eventually led to the expulsion of hundreds of U.S., British and Russian diplomats from both sides of the fight, CBS News foreign correspondent Charlie D'Agata reports.