Two pensioners who stood up for a young woman reportedly harassed by a migrant were apparently attacked in Germany by a group of refugees, according to a video.

The mobile phone footage posted online appears to show a group of young migrants of eastern European or Arabic origin attacking two German pensioners on a busy train in Munich in the middle of the day.

In the video the migrants are seen holding one man by the arms as he is verbally abused, while the second pensioner tussles with one of the young men before being held up by the neck and threatened.

The fight allegedly broke out after one of the migrant men was rejected by a woman whom he had placed his hand upon on the train.

A man named Tom Roth, who filmed and posted the video on his Facebook page, wrote alongside the video that one of the men said something to the woman and then asked: “Why will you not answer me in German?” The woman reportedly replied: “Because you asked me in English.”

Mr Roth wrote: “I think he had his hand on her back. She turned away and looked in my direction.

“As the train continued, the asylum seeker struck the glass window full force. I guess he was angry the woman rejected him. Several men shouted at him to stop.”

But when they did, one elderly German man was patted mockingly on the head by one of the migrant group, sparking an angry exchange.

“The gentleman stood up right away,” wrote Mr Roth. “The asylum seeker then turned, approached the man and grabbed him by the neck. Everyone immediately became involved, with many trying to get in between the pair.”

“The man's attacker fell back in his four-seater. There were four asylum seekers now involved, staring at us and two other older gentlemen angrily.

“There were about 10-15 people beside and behind me. The situation was brought under control. When the train reached the station I called the police. They said there was nothing they could do.”

Mr Roth said he felt the need to share the video, adding: “Those involved were very distressed. An older lady said she doesn't leave her home at night any more. The two gentlemen said that it cannot go on like this.

“I felt safer in Germany two or three years ago. I find that terrifying and sad.

“I'm really sorry for the people who need help, but something must happen against the violent and disrespectful people among them. Many asylum seekers have no respect for women, no respect for men - not even the old - let alone our laws and the police.

A spokesman for the Munich Police Department told the Telegraph that the video was "real and investigations are ongoing".

The police confirmed that they were made aware on Sunday of the incident that is understood to have taken place on January 30, and that they wanted to get in contact with the man who posted the video.

Officers want to clarify with the help of witnesses how the situation escalated and how it ended, as only a part of what happened was captured on the video. They also want to ascertain whether the culprits are definitely refugees.