London Tube station evacuated amid reports of smoke

One of the busiest stations on London's subway system has been evacuated and firefighters say they are investigating reports of smoke.

London Fire Brigade says crews have been called to Oxford Circus station. British Transport Police say the station is shut because of a fire alert.

Passenger Tom Singer tweeted a photograph of smoke filling a carriage of a Bakerloo Line train at the station

Passengers say staff ordered everyone to leave around 9 a.m. (0800GMT) Friday.

There were no immediate reports of injuries.