A man was stabbed Thursday in front of the Interior Ministry in central London, police said, who made an arrest.
Contrary to what she announced at first, the police said that the victim's days were not in danger.
"A man was arrested, suspected of causing serious bodily harm, and taken to the police station"she said, saying that she still needed to determine"the exact circumstances"aggression.
The police, who were alerted shortly after 13h local (12h GMT), cordoned off the area.
A photo broadcast by British media shows a man standing, escorted by the emergency services, his face covered with blood and a rag. He is shirtless, a suit jacket placed on his shoulders, and his belly covered with blood.
"We intervened on a man on the spot and took him to a major trauma center", said London ambulance services.
"All my thoughts are with the victim and his family after this horrible, unjustified knife attack", tweeted Interior Minister Priti Patel.
The attack came as the Home Office had just launched an awareness campaign to try to stem the scourge of knife attacks in the UK.
According to the National Office of Statistics (ONS), 43,516 stabbings were committed in England and Wales during the 12 months ended March, up 8% from the previous period.