St Paul's Cathedral said it was beefing up security after a suspected gunman was arrested outside the cathedral on Friday.
The cathedral and City of London Police said there was "no indication" that the incident was terror-related and that the historic landmark would be open as usual over the weekend, although with increased security.
City Police confirmed they had arrested a man believed to have been in possession of a firearm shortly after midday.
According to the BBC, a man pointed a weapon at security staff in the Cathedral's crypts and pulled the trigger but no bullet was fired. He attempted to flee the scene and discarded the weapon before being detained by the police.
St Paul's said in a statement that it was putting extra security staff on duty and increasing screening at entry points but that the building would remain open for visitors.
"Shortly after midday on 29th March 2019 a man was arrested by the City of London Police who was believed to be in possession of a firearm. He was detained behind One New Change by armed officers. There is no indication that this incident is terror related at this time," it said.
Although an entrance to St Paul's was cordoned off after the incident, the popular London landmark remained open for the remainder of Friday.
The cathedral added: "The safety and security of all our staff and visitors are of the utmost importance. Additional security officers will be on duty at the Cathedral today and over the weekend, with increased security screening taking place.
"The cathedral will remain open today and over the weekend as usual."
