Security guards said the armed siege at London's Trocadero Centre was over, as staff arrived for work as usual.
The alarm was raised when two armed men overpowered security guards in the early hours of Tuesday morning, Scotland Yard said.
But police confirmed the incident was over and said an investigation was being carried out at a West End police station.
The armed men are believed to have targeted the Funland amusement arcade, which spans several floors in the shopping and entertainment complex. They gained entry to the centre and threatened and then "restrained" security guards.
One of the guards managed to escape and raised the alarm at 3.40am.
Shaftesbury Avenue was sealed off for a police investigation.
A security guard, who did not want to be named, said: "This is a very secure building normally. It's very easy to set the alarms off even when you're doing your job overnight. The night security guards have to do an external inspection of the building every two hours, so it's funny how this could have happened".