An 11-year-old girl and 34-year-old woman were injured in central London, UK police say.

Police in the United Kingdom say they have arrested a man after a stabbing in London’s Leicester Square that left an 11-year-old girl needing hospital treatment and a 34-year-old woman with minor injuries.

The police said the incident on Monday in the central London square, an area popular with tourists, was not being treated as “terror-related”.

The stabbing occurred as the UK is on edge after violence over the past week saw crowds spouting anti-immigrant and Islamophobic slogans and clashing with police. The disturbances have been fuelled by right-wing activists.

The square where Monday’s attack took place and the surrounding area have an estimated 2.5 million visitors every week and are home to shops, theatres, cinemas and restaurants.

The injuries of the 11-year-old victim were not life-threatening, the police said, adding that she was being treated in hospital.

There were no other outstanding suspects, police said.

The Guardian newspaper quoted a security guard as saying he “jumped on” the attacker and took the knife from him.

The 29-year-old guard, who gave his name as Abdullah, told the PA news agency: “I heard a scream. At that moment, I saw there was one person, roughly [in his] mid-30s or early 30s, and he was like stabbing a kid. I jumped on him, held the hand in which he was [carrying] a knife and just put him down on the floor and just held him and took the knife away from him.

“Then a couple of more people joined as well, and we just held him until the police came. It took maybe three to four minutes for the police to arrive, and then they just took him into custody.”

The UK’s police forces remain on high alert after the recent riots, which were triggered by online posts wrongly identifying the suspected killer of three girls at a stabbing during a Taylor Swift-themed dance event in northern England as a Muslim migrant.

It was not immediately clear whether the latest stabbing had any link to the unrest.

Police had braced for further riots over the weekend, but no widespread unrest emerged. Ministers remained on high alert, Prime Minister Keir Starmer’s office said, adding the government’s work was not done in dealing with the fallout from the violence.