King's Cross Station has been closed to the public on Tuesday morning after emergency services were called to a "fire alert".
A spokeswoman for the British Transport Police told DailyStarOnline: "We were called at 10.48am to reports of a fire alert. We are currently on scene supporting the fire brigade, and the station has been closed as a precaution."
And a London Fire Brigade spokewoman added: "We were called to reports of a fire alarm sounding at King's Cross Station at 10.43am.
"We arrived to discover smoke build up in a communications area."
Eyewitnesses took to social media to report "many firefighters and police officers right now as King Cross Underground Station's being evacuated".
In October last year, the major London station was evacuated after football fans let off a flare inside the building.
On October 3 2019, Belgian football fans let off flares before their Europa League clash with Arsenal.
Police were called after the explosives were sparked by excited Standard Leige fans.
People who were caught up in the outburst used social media to thank Transport for London staff for their help.
One said: "A big thank you to your brilliant staff at Kings Cross for keeping passengers safe and calm during an evacuation, when football supporters started setting off fireworks on the Underground.
"Grateful we’re in good hands. Please pass on my thanks."
Others used the platform to share their disgust, calling for the crowd to be arrested.
Tagging the Metropolitan Police in the Tweet a woman said: "Very much hope the @metpoliceuk are going to arrest every single one of the massive crowd of utter hooligans who just let off a load of bangers at #KingsCross in crowds including pregnant women and small babies then marched off chanting past St Pancras."