The victim, aged 16, was with two friends in the western city of Cologne late Saturday when the 1.2 metre (four-foot) robot approached her, police said.

The device, coloured red and gold, is then alleged to have touched the girl on the buttocks and performed thrusting motions, they said.

The 16-year-old male, allegedly the owner, and the 19-year-old man are "said to have filmed the alleged assault, streamed it live on social media, and commented on it," said a Cologne police statement.

A video circulating on platform TikTok shows a red and gold humanoid robot, accompanied by two males, pressing up against a teenage girl, who screams and moves away.

Police were alerted and found the robot in a car boot, where the owner is suspected of having hidden it.

Authorities seized the robot and two phones belonging to the suspects, who are now under investigation.