MDMK leader Vaiko and scores of his supporters were Friday arrested after BJP and MDMK volunteers clashed in Kavalkinaru area on the border of Tirunelveli and Kanyakumari districts of Tamil Nadu, police said.
Vaiko had announced that black flags would be shown to Prime Minister Narendra Modi to protest against his visit to Tamil Nadu.
He gathered at Kavalkinaru along with his supporters and gave a speech listing out the alleged betrayal of the state by the Central government on various issues including Cauvery.
Even as Vaiko was speaking, MDMK and BJP cadres clashed, throwing stones at each other, police said.
Police swung into action and arrested Vaiko and his party workers.
MDMK men carried placards which read "Modi go back as you betrayed Tamils."
Police said BJP volunteers also demanded the arrest of Vaiko, adding he was spreading lies about the Central government.
Police said as many as 100 people had been arrested.
Vaiko and his party cadres were refused entry into Kanyakumari district by the police and stopped at the border.
The Prime Minister is currently in Kanyakumari to inaugurate a number of welfare projects.