Police are searching for another person believed to be involved in an affray in the Regent Street area at around 4pm.
A 16-year-old boy has been arrested and is tonight at hospital receiving treatment for a non-life threatening stab wound.
A West Yorkshire Police spokeswoman said: "Police are investigating an affray involving two males which is reported to have occurred in the Regent Street area of Leeds at around 4pm this afternoon (Monday, 7 January).
"A 16-year-old boy has been arrested and is currently at hospital receiving treatment for a non-life threatening stab wound.
"Enquiries are ongoing to trace another male who is believed to have been involved."