By Emma Simpson BBC News, Moscow

Authorities say that a group of around 15 youths attacked the three foreign students at a sports complex in the city of Voronezh.

Earlier this year, a human rights group warned that racism was growing at an alarming rate in Russia.

Prosecutors have yet to indicate a motive for the latest attack.

One of the students, a Peruvian national, was killed and the other two, from Spain, are in hospital with serious head injuries.

Spate of violence

Voronezh is a big college town: since Soviet days it has hosted hundreds of foreign students every year.

But it seems to be acquiring a rather ugly image as a place of racial intolerance.

Over the past six years, at least seven foreigners have been killed in what appear to be racially motivated attacks.

A year ago, a group of skinheads murdered a student from Africa. They were caught and convicted.

According to the Moscow Bureau of Human Rights, racism and xenophobia are on the increase in Russia.

They say there have been three times as many fatal attacks in the first six months of this year, compared with the whole of last year.

Russian President Vladimir Putin has acknowledged the seriousness of the problem.