A WOMAN with ‘deep psychological problems’ was in custody in the French city of Marseille today after spraying four American tourists with acid and burning two in the face.

The horrifying attack took place shortly after 11am at the St Charles station, where the party from the States was preparing to board a train.

5 Michelle Krug was among a group of four American tourists who suffered burns when acid was thrown over them in Marseille today Credit: Facebook

5 Kelsey Kosten, a fellow Boston College student was also among the injured during the attack Credit: Facebook

5 Charlotte Kaufman was the third victim of the hydrochloric acid attack Credit: Facebook

5 Courtney Siverling was caught up in the horror attack in Marseille Credit: Facebook

Last night the victims were named as Boston College students Courtney Siverling, Charlotte Kaufman, Michelle Krug and Kelsey Kosten.

Their 41-year-old attacker used a cleaning substance containing hydrochloric acid that she is thought to have picked up from a DIY store.

Two of the victims - all of whom were aged 20 or 21 - were sprayed in the legs, and were mainly suffering from shock’ said a source close to the case.

The other two students suffered facial injuries and were taken to hospital, while the others were treated at the scene.

The attacker was arrested at the scene.

According to witnesses, no slogans were shouted out during the attack, and it was not thought to be terrorist related.

Prosecutors have opened a criminal enquiry, while none of those involved have yet been named.

5 Four American tourists, identified as Boston College students have reportedly had acid hurled in their face outside Marseille train station this morning Credit: Alamy

The Americans were thought to be on their way from the southern Mediterranean city to Paris.

Four emergency services vehicles arrived at the station, which was packed on a Sunday morning at the tail-end of the holiday season.

Paris remains under a State of Emergency following a string of terrorist attacks carried out by Islamic State and Al-Qaeda operatives over the past two years.

Security at transport hubs including rail stations has been massively stepped up because of threats by the groups to target them.

Corrosive substances are increasingly being used as weapons in Europe, including in Britain, where there were 450 such attacks in London alone in last year.

Acid-based products are easy to purchase, and can be paid for in cash, so there is no trace of who bought them.