Batley and Spen MP Jo Cox was shot and stabbed on the steps of Birstall Library, near Leeds.
A West Yorkshire Police spokesman said: “At 12.53pm today, police were called to a report of an incident on Market Street, Birstall, where a woman in her 40s had suffered serious injuries and is in a critical condition.
“A man in his late 40s to early 50s nearby also suffered slight injuries.
“Armed officers attended and a 52-year-old man was arrested in the area.”
The spokesman added that police presence in the area has been increased as a reassurance to the community.
For a video of the scene and the latest updates, click here.