Unknown attackers launched a tear gas attack on a train in Hamburg that reports say has injured at least six and affected 50 people and led to a massive police presence at the Hamburg train station.

At 6:55 pm Friday evening passengers on a train in Hamburg on the S-Bahn line 11 were subjected to a tear gas attack by two young men affecting 50 including a three-year-old girl. Paramedics and police arrived on the scene to treat the passengers of the train for various ailments including respiratory injured German paper Bild reports.

The attack occurred just before the train reached Sternschanze station in the centre of Hamburg and upon arriving all passengers fled into the station to escape the gas.

Federal police at the train station said that the perpetrators were likely two young men who had fled the scene. Rüdiger Carstens, spokesman for the federal police said, “The recordings of the surveillance cameras were secured. The investigations continue.”

Less than a month ago Hamburg airport had to be partially evacuated as the result of a similar attack. In that attack, an unknown toxin was released through the airport’s ventilation system and it led to 68 people needing treatment for irritated eyes and breathing difficulties.

The Hamburg metro system also saw an attack on a woman earlier this year when a Morrocan migrant pushed her onto the train tracks of the subway. The 34-year-old woman was pushed by the 16-year-old and was knocked out due to the fall from the platform. Before the attack CCTV footage revealed the 16-year-old attempted to rob the woman.

The attack also follows a 24 hour period which has seen an axe attack on a train and at the main railway station in Dusseldorf and a machete attack that injured an 80year-old man in Dusseldorf earlier on Friday.

Correction: Due to a translation error, the original version of this article said 50 people were injured. In fact 50 people on the train were affected and at least six people are known to have been injured so far.