16-year-old climate change activist, Greta Thunberg, has become involved in a strange online spat with a German train company after tweeting a photograph of her sitting on the floor of a train carriage.

Thunberg, who was later upgraded to first class, tweeted a photo of herself sitting on the floor of a busy train travelling through Germany, with the caption "Traveling on overcrowded trains through Germany. And I'm finally on my way home!"

This appeared to incense the train company that was operating the service, however.

Deutsche Bahn (DB) took to Twitter to reply, "Dear #Greta, thank you for supporting us railroad workers in the fight against climate change! We were pleased that you were on the ICE 74 with us on Saturday. And with 100 percent green electricity."

"It would have been even nicer if you had also reported how friendly and competent you were looked after by our team at your seat in first class," they added.

Thunberg was quick to diffuse the situation, responding "Our train from Basel was taken out of traffic. So we sat on the floor on 2 different trains. After Göttingen I got a seat. This is no problem of course and I never said it was. Overcrowded trains is a great sign because it means the demand for train travel is high!"

"

Deutsche Bahn then proceeded to release a press release where they confirmed that the activist and her companions "were sitting in first class from Frankfurt onwards".

16-year-old climate change activist, Greta Thunberg, has become involved in a strange online spat with a German train company after tweeting a photograph of her sitting on the floor of a train carriage.

Thunberg, who was later upgraded to first class, tweeted a photo of herself sitting on the floor of a busy train travelling through Germany, with the caption "Traveling on overcrowded trains through Germany. And I'm finally on my way home!"

This appeared to incense the train company that was operating the service, however.

Deutsche Bahn (DB) took to Twitter to reply, "Dear #Greta, thank you for supporting us railroad workers in the fight against climate change! We were pleased that you were on the ICE 74 with us on Saturday. And with 100 percent green electricity."

"It would have been even nicer if you had also reported how friendly and competent you were looked after by our team at your seat in first class," they added.

Thunberg was quick to diffuse the situation, responding "Our train from Basel was taken out of traffic. So we sat on the floor on 2 different trains. After Göttingen I got a seat. This is no problem of course and I never said it was. Overcrowded trains is a great sign because it means the demand for train travel is high!"

"

Deutsche Bahn then proceeded to release a press release where they confirmed that the activist and her companions "were sitting in first class from Frankfurt onwards".