A Swedish man suffered knife injuries when an argument got out of hand late on Saturday night.
The police said they were alerted to the incident in an apartment in Triq is-Snajja, Msida, just before midnight.
They found that a 30-year-old Swedish man who lives in Sliema was injured with a sharp and pointed object by a man whose identity is not yet known.
An ambulance took the victim to Mater Dei Hospital where he was later certified as suffering from grievous injuries.
Police investigations are still underway.