A homeless man in Stockholm
A homeless man in Stockholm suffered facial injuries in an unprovoked hate crime attack (Reuters)

Acid was hurled on two EU immigrants begging on the streets of Stockholm, Sweden, in what police believe to be an unprovoked hate crime.

A male and a female immigrants were attacked with acid in Berzalii Park in central Stockholm on Friday.

The male immigrant suffered burns to his face, and was taken to Karolinska Hospital in Solna, where he was treated by doctors wearing protective clothing. A female immigrant was uninjured, police told local media, as the acid landed on the back of her jacket.

"He had a swollen face and was taken to hospital. His injuries are unclear and we do not know how extensive they are," police spokesman Tommy Dimitrakis told the Swedish newspaper Aftonbladen.

A passer-by gave chase to the attacker, but was unable to catch the offender.

"The offender ran from the scene and a witness chased him but could not catch up," Dimitrakis said.

"It is a terrible act, of course, and now we are investigating."

The injured man was discharged from hospital on Saturday.

It is not known what kind of acid was used in the attack, said officials.

The homeless have been targeted in a number of attacks in the Swedish capital recently, reports the Local.