Trafalgar Square in London was put on lockdown after a suspicious vehicle was found there on Saturday, Metro reported.
The area where the vehicle was found was cordoned off, while law enforcement and the fire brigade were working at the scene.
Earlier in the day, journalist for Global News, Crystal Goomansingh, tweeted that a controlled explosion took place near Trafalgar square where officers were dealing with a suspicious vehicle.
Metro is quoting a tourist who said she was in Trafalgar Square with her son, when they heard "the sound of a ‘bomb’ go off ‘without any warning".
According to Westminster Police, the incident is not linked to terrorism. However, the police did not elaborate on what exactly happened.
The incident comes amid large-scale celebrations of the Platinum Jubilee which marks 70 years since Queen Elizabeth II took the throne. Some 20,000 people are expected to attend the open-air concert outside Buckingham Palace tonight.