Three people have been injured in London after a “chemical substance” was delivered to a Borough Market restaurant in an envelope.

The unidentified substance, believed to have been corrosive, was sent to Feng Sushi restaurant on Stoney Street - one of the locations targeted by the London Bridge terrorists in June.

Unconfirmed report of acid/corrosive incident in borough Market attracts fire, police and ambulance attendance. pic.twitter.com/6PQsxUtTTu — Paul Dawson (@poleydee) August 10, 2017

Police fire and ambulance dealing with unknown substance in Stoney Street opposite Borough Market https://t.co/Mm7bUrttKmpic.twitter.com/hly56aXOsy — London SE1 (@se1) August 10, 2017

Fire engine and ambulance outside Feng Sushi, Borough Market. Police cars in area. Workers say due to "chemical package" not acid attack pic.twitter.com/aACC0C0PTd — Peter Yeung (@ptr_yeung) August 10, 2017

The restaurant has been evacuated as a precaution and cordoned off by police.

The Metropolitan Police said the incident is not being treated as terrorism related “at this early stage.”

London Fire Brigade said firefighters using protective equipment were inside the building after they were called to assist police with a “chemical incident” shortly before 2pm local time.

Police said they were called to reports of an “unidentified substance being delivered in an envelope” to a business in south east London.

Police are on scene in #BoroughMarket after an unknown substance was delivered to a... https://t.co/ZZZKceOXiMpic.twitter.com/LCusWeKHZx — Metropolitan Police (@metpoliceuk) August 10, 2017

Three people are being treated for minor injuries.

Police said no arrests had been made and enquiries continued.