A couple on a London night bus have said they were beaten up by a group of men who turned violent after they refused to kiss. 

Melania Geymonat, 28, said she and her girlfriend were attacked by the men while they were riding a double decker bus in the early hours of May 30. 

Both women were taken to hospital and treated for facial injuries following the incident, which London mayor Sadiq Khan described as a "disgusting, misogynistic attack". 

"Hate crimes against the LGBT+ community will not be tolerated in London," he wrote on Twiter. 

Ms Geymonat said that the group of men had first started taunting the couple after discovering that they were lesbian, urging them to kiss and making sexual gestures. 

Writing on Facebook, she said she tried to calm things down by cracking jokes, but that did not work. 

"They kept on harassing us, throwing us coins and becoming more enthusiastic about it.

"The next thing I know is I'm being punched. I got dizzy at the sight of my blood and fell back. I don’t remember whether or not I lost consciousness. Suddenly the bus had stopped, the police were there and I was bleeding all over". 

The aggressors are believed to have stolen a phone and bag belonging to the couple before fleeing. 

Scotland Yard have said they are investigating and London police have urged any potential eyewitnesses to come forward.