A man is being questioned on suspicion of stabbing two men to death in a city centre on Friday night, police said.
The men, who are believed to be in their 40s, were stabbed in Birmingham city centre just before 6pm.
West Midlands Police said one victim is understood to have been stabbed outside a Sainsbury's store on Martineau Place while the second man was found slumped near Boots in Union Street.
Officers gave first aid to the men but both were pronounced dead at the scene.
A man was arrested in New Street near the Odeon Cinema minutes after the stabbings.
Inspector David Keen said: "Two men have suffered fatal injuries - these have been inflicted in the heart of the city at a busy time when workers and shoppers would be heading home.
"There are potentially hundreds of witnesses, either people who saw the stabbings or the offender leaving the scene, and I'd urge people to get in touch immediately - they could have vital information.
"A large police presence was quickly on the scene and a man was arrested swiftly."
An area of Union Street has been cordoned off while officers carry out forensic investigations.
Anyone who witnessed the incident or has any information is asked to call police on the 101 number.