Four American women traveling in southern France were attacked with acid Sunday at a train station in Marseilles, a police spokeswoman said.

All four of the women were taken to a hospital for burn treatment, though two were mostly uninjured, according to the New York Times. One of the women had been hit in the eye with the substance and could not see well, TV station France 3 reported.

All four of the Americans were university students in their early 20s studying abroad.

A statement from Boston College identified them as Courtney Siverling, Charlotte Kaufman and Michelle Krug — students in the school’s Paris program — and Kesley Korsten, who studies at the Copenhagen Business School in Denmark.

“It appears that the students are fine, considering the circumstances, though they may require additional treatment for burns,” Nick Gozik, who directs school’s international programs, said in the press release.

All four women were in their third year of studies, the university said.

The attacker was a 41-year-old woman who is mentally unstable, police said. She was arrested and hospitalized, according to CNN affiliate BFM.

A French-language report states the alleged attacker remained at the scene and displayed pictures of herself with burns, the BBC reported.

Authorities added there’s no indication the attack was terror-related.

Acid attacks have long been a problem in several south Asian countries, but Europe recently has seen an increase in the incidents. Most notably, police in London recorded 454 acid attacks last year, almost triple the number on record in 2012.

In the incidents, Assailants typically approach their victims and throw some cocktail of corrosive chemicals on them, burning their flesh, disfiguring their faces and bodies and causing excruciating pain. They are rarely fatal, but all it takes is a few seconds and a splash to derail a life.