The US Embassy was placed in lockdown as armed officers swooped on a suspicious package that is now thought to have been a hoax device.

Armed officers from the Met Police arrived at the building in Nine Elms, south west London, following reports of a suspicious package on at around 10am on Friday.

The embassy was immediately locked down as a police unit carried out a controlled explosion of the item within a cordoned area, said to have caused a loud bang.

People who had been queuing up for visa appointments were locked inside for more than an hour before being sent home while staff remained inside as officers searched the area.

In a statement at around 1pm, the force said: “Initial indications are that the item was a hoax device. An investigation will now follow.

“Some cordons will remain in place for the time being but the majority of the police response will now be stood down.”

In a statement posted on social media platform X at about 10am, the Metropolitan Police said: “We can confirm that the ‘loud bang’ reported in the area a short time ago was a controlled explosion carried out by officers.”

The embassy is in a high-rise, residential area close to the Thames, with the cordons meaning people who live in the area were unable to get back into their homes.

Firefighters were also at the scene, as well as the dog squad, with dozens of people - many of them people who were attending the building for visa interviews - told to stay behind barriers while authorities responded.

Kevin Tinkler from Aberdeen told the Independent he had been waiting outside for two hours. “There’s been a definite lack of information from the police. The only piece of information I’ve been given was that I was advised to come back another day and rebook the appointment,” said Mr Tinkler.

Another bystander, Jim Prevot, said there were a few hundred people inside having visas processed while the incident was unfolding.

One woman at the scene, who did not want to be named, said she and a companion had been in the building for about three hours. “We didn’t hear anything, it was very calm and chilled in there,” she said. “The cafe stayed open and the amazing thing was they continued processing visa applications throughout the morning. They handled it really well.”

A woman who gave her name as Kawtar said she had been in the embassy since 8am. “Honestly it was calm inside, but we got told we shouldn’t be outside. I’m only now figuring out that something is going on, because nobody knew what was going on,” she said.

The US Embassy said in a statement on X police were investigating the package left outside the building. “Met Police are present and have closed Ponton Road out of an abundance of caution. We will provide further updates when available,” the embassy said. 

The drama unfolded at the same time Gatwick Airport evacuated “a large part” of the South Terminal due to a security incident.

The Sussex airport confirmed the news in a social media post, with passengers expected to face disruption to their flights. “A large part of the South Terminal has been evacuated as a precaution while we continue to investigate a security incident,” a statement read. By Millie Cooke and Angus Thompson, The Independent