ISTANBUL

A terminal at London's Heathrow Airport was evacuated due to a "possible hazardous materials incident" on Monday, according to Sky News.

The check-in area of Heathrow Airport's Terminal 4 was closed while the emergency services responded to a "possible hazardous materials incident."

An airport spokesperson advised passengers not to travel to the terminal in west London while other terminals are operating as normal.

"Specialist crews have been deployed to carry out an assessment of the scene, and part of the airport has been evacuated as a precaution whilst firefighters respond," a London Fire Brigade spokesperson also told Sky News.

Images circulating on social media reportedly seemed to show several ambulances stationed outside Terminal 4 of the airport.

An airport spokesperson reaffirmed that the terminal is now "safe to reopen" after around 20 people were assessed at the scene by paramedics.

A spokesperson for the Metropolitan Police said: "No trace of any adverse substance was found."

Although around 20 people reported an injury, none were reportedly deemed to be "life-threatening" while inquiries are ongoing.