As many as 36 police have been injured in clashes with protesters in India’s southern state of Kerala.
Demonstrators were demanding the release of a person arrested during a demonstration against a $US900 million ($1.34 billion) port project of the Adani Group.
The growing agitation has become a major headache for Adani’s ports and logistics business, which is worth $US23 billion.
The location of the port on India’s southern tip was seen as key to winning business from ports in Dubai, Singapore and Sri Lanka.
Construction at the Vizhinjam seaport has been halted for more than three months since protesters, mostly drawn from the fishing community, blocked its entrance, blaming the development for coastal erosion and saying it is depriving them of their livelihoods.
Over the weekend, protesters blocked Adani’s construction vehicles from entering the port, despite a court order for work to resume, prompting the arrest of many of them.
That spurred hundreds more to gather at a police station on Sunday night, demanding the release of those arrested.
Clashes with police followed, causing damage to some of their vehicles, television news images and a police document showed.
“They came with lethal weapons and barged into the station and held the police hostage, threatening that if people in custody were not released they would set the station on fire,” the police said in the case document on the incident.
Many of the protesters were Christians led by Roman Catholic priests.
Police attacked the protesters, among whom were some priests, said a clerical official, Eugine H Pereira, the vicar general of the archdiocese.
“Stones were pelted from even the station,” Mr Pereira said, calling for a judicial inquiry into the incident.
The Adani Group did not immediately respond to a request for comment.
It has earlier said the project complies with all laws, citing studies in recent years that have rejected accusations linking it to shoreline erosion.
The state government blames the erosion on natural disasters.