A police officer stands outside Parsons Green tube station in London, Britain September 15, 2017.

:: Heavily armed police rushed to an incident at a London underground station on Friday with local media reporting there had been an explosion on a train.

A Reuters witness could see six ambulances, fire engines and a helicopter at Parsons Green station in West London where the Metro newspaper reported that passengers had suffered facial burns from a blast and others had been hurt in a subsequent stampede.

Outside the station, a woman was sitting on a pavement with a bandage around her leg while armed police patrolled. A Reuters witness saw a woman being carried off on a stretcher with her legs covered in a foil blanket. “We are aware of an incident at #ParsonsGreen tube station. Officers are in attendance,” London police said on Twitter.

Police said they were aware of reports on social media and would release facts regarding the incident once they could be sure of their accuracy. London Ambulance and Fire Brigade said paramedics and firefighters were present.

Transport for London said on Twitter that there was no service between Earls Court and Wimbledon on the District Line which runs through Parsons Green. Britain has already suffered four attacks blamed on terrorists so far this year which killed 36 people.

In this image made from video, fire raises at a southwest London subway station in London Friday, Sept. 15, 2017.

An armed British police officer works near Parsons Green underground tube station in west London on September 15, 2017, following an incident on an underground tube carriage at the station.