Crowds of people were seen chanting and cheering on Thursday evening as a car was pushed down a steep hill into bollards while another car was set alight.
One photo shows two cars on fire in the middle of the street surrounded by smoke while the crowds gathered around them.
In another video people are seen throwing objects and shouting at retreating police using riot shields.
South Wales Police issued a statement at around 10.45pm on Thursday which said: “A number of our officers are at the scene of large-scale disorder in the Mayhill area of Swansea. Residents are urged to stay indoors while the matter is brought to a safe conclusion.”
Superintendent Tim Morgan said: “What is believed to have started as a vigil to a recently-deceased local resident has escalated into violence, criminal damage, and a wanton disregard for public safety.