Police have launched an investigation after a vandal attacked a local LGBT+ community centre on Pride weekend, leaving staff and volunteers stunned.

At around 10.05am on Saturday (June 27), bystanders watched in horror as a man with a golf club smashed the windows of Oakland LGBTQ Community Centre in California.

Described as “a young skinny white male”, he is said to have yelled expletives while striking the building before fleeing the scene on a bike when confronted by nearby vendors.

The all-inclusive centre was founded by two gay African American men, who have described the attack as a hate crime.

“Our organisation is Black lead and queer,” they wrote on Facebook. “We have a large banner on our window that says Black LGBTQ Lives Matter Too!

“We are clear that this was a hate crime that could have caused us to be targeted because we are Black and because we are LGBTQ.”

They said the attack has “rattled” the team, but added: “We will get through this.”

One eyewitness, Cosmos Ozansi, told ABC7 News that he was setting up his jewellery stand on the street outside the centre when he saw the angry-looking man striking the windows.

“[I yelled] ‘Stop, stop!’ as loud as I could, then he saw me.” He says the man turned and rode away on his bike.

Oakland mayor Libby Schaaf was outraged by the act of vandalism. “I am furious that anyone would commit this kind of act at this sanctuary of love, pride and family,” she said.

Oakland Police say they are actively investigating the incident.

Oakland LGBTQ Community Centre has thanked those who arrived to help them clean up the mess, as well as “everyone offering support to us through this difficult and emotional time. We appreciate you so much.”

The group has requested donations via their website, and urged people to contact the local police department and ask them to make hate crimes against Black and LGBT+ people a priority in Oakland.