Police are asking witnesses to step forward after a fight in Vancouver's Yaletown neighbourhood that sent three to hospital.

Officers said the incident occurred Sunday morning at around 1:30 a.m. Two groups of people met while walking on Mainland Street near Nelson Street.

A fight broke out between the groups, and three men involved in the altercation were stabbed, Vancouver police said in a statement.

Police said a 29-year-old Surrey man was taken to hospital with serious injuries, but his condition is not believed to be life-threatening.

Two others, a 25-year-old man from Vancouver and a 26-year-old man from Richmond, were also taken to hospital for minor injuries. They have since been released.

Six men were arrested, but all were released without charges.

The investigation is ongoing, and anyone with more information or dashboard camera footage is asked to contact police. Tips can be left with the VPD at 604-717-2541 or anonymously through Crime Stoppers.