Eight paramilitary soldiers from India's Border Security Force (BSF) have been suspended after they were filmed assaulting a man, officials say.
The incident, which took place on the border with Bangladesh in West Bengal state, has caused an uproar.
A video, shot on mobile phone and shown by some TV channels, shows the soldiers stripping and assaulting a suspected cattle smuggler in Murshidabad.
The BSF has ordered a probe into what it called a "despicable" incident.
"There is no doubt that the act is a despicable one. It is evident that eight soldiers were involved in this incident which happened on 9 December," senior BSF official Ravi Ponoth told the BBC.
Mr Ponoth said the soldiers were on duty at the a border outpost in Raninagar area of Murshidabad.
The grainy video shows a young man being stripped, bound to a bamboo pole, and beaten by the soldiers. It is not clear who shot the video.
A Calcutta-based rights group, Masum, said they had information that three young men - two of them Bangladeshi nationals - had been held by the soldiers on the border.
"Later, one of the Bangladeshi men was mercilessly beaten up," said Kirity Roy, secretary of Masum.
Cattle smuggling across India's border with Bangladesh is common, and villagers on both sides have been found to be involved in it.