Emergency services have been called to a restaurant in Britain's Salisbury Sunday after two people fell ill.

Wiltshire Police said the area surrounding Prezzo restaurant has been closed while they work to establish what caused the "medical incident" involving a man and a woman.

The police said the ambulance service alerted detectives at about 6:45 p.m. and firefighters were also in attendance.

"As a precautionary measure, the restaurant and surrounding roads have been cordoned off while officers attend the scene and establish the circumstances surrounding what has led them to fall ill," said the police.

A witness named Sam Proudfoot told Daily Mail he saw a person in a hazardous material suit go between the restaurant and the ambulance.

"I've been told two people were taken ill in there," he said: "There's a man in a full white body suit with a mask to his mouth going in and out of the back of the ambulance and the restaurant."

Some local reports said the Prezzo restaurant is not far from the restaurant where Sergei and Yulia Skripal were poisoned earlier this year.