An arts centre has apologised for any "distress caused" by a loud fireworks display which sparked panic in the capital, just days after the London Bridge attack and the Grenfell Tower disaster.
Somerset House said the display was not organised by the institution, but was linked to a private event taking place in its grounds.
Members of the public went online to voice their distaste for the loud show of celebration late on Friday, with some passers-by fearing another terrorist atrocity was taking place.
Lilly Roberts, 29, who works for the front of house team at the nearby Novello Theatre, told the Press Association she saw five or six members of the public running down the street in panic.
She said: "I just heard this almighty crash.
"Obviously, with everyone being on a bit of tenterhooks from the attacks a couple of weeks ago, the first thing I thought was 'Oh my God.'
"I've heard fireworks but I've never heard them that loud before. There were some people running up the street away from the explosion, because I guess they thought the same thing about the explosions: that we were under attack."
Ms Roberts said the "horrible" bangs appeared to be emanating from Somerset House.
Footage from eyewitnesses confirmed the scale of the display, which featured multicoloured bursts of colour and rapid-fire gunshot noises over the Thames.
Twitter user Alison Hamilton tweeted: "Fireworks from a private event in London. I find that incredibly distasteful in light of what has happened over the past few weeks here."
Another user, Harry Barrett, also criticised the event, and said: "Of all the times to spontaneously set off fireworks in central London, this is absolutely not it."
A spokeswoman from Somerset House said: "We are very sorry for the distress caused by fireworks in the River Thames near to Somerset House last night.
"These were not organised by Somerset House, but were linked to a private event taking place here.
"The event organisers sought all the correct permissions for the fireworks from the relevant authorities. However, we regret that their plans for the evening were not sufficiently reviewed in light of the tragic recent events in the city.
"We know this is a time of great sorrow, sensitivity and pain for Londoners and everyone at Somerset House stands in solidarity with all those affected."
Eight people lost their lives in an attack on nearby London Bridge and Borough Market on June 3, which followed further atrocities in Westminster and Manchester earlier this year.
At least 30 people have now died as a result of a devastating fire in the Grenfell Tower apartment block in north Kensington on Wednesday, although authorities say the figure is expected to rise significantly.