LONDON: British police said yesterday that two people are in a critical condition in a Salisbury hospital after being exposed to an "unknown substance" not far from where former Russian spy Sergei Skripal and his daughter were poisoned, reports AFP.

Police said they considered the situation a "major incident." The two patients "are both currently receiving treatment for suspected exposure to an unknown substance at Salisbury District Hospital," Wiltshire police said. "They are both in a critical condition".

The two people, a man and a woman both in their 40s, were discovered unconscious on Saturday June 30 at a house in the village of Amesbury, which is around 12 kilometres (eight miles) from Salisbury.