Telangana leaders from Telugu Desam, TRS and BJP were taken into custody by the police on Thursday as they proceeded to take part in the 'million march to Hyderabad' protest.
Police have denied permission to the march, slated to take place from 1 pm to 4 pm.
The TRS MLAs were taken into custody soon after they started marching toward the Tank Bund at Hussain Sagar lake here, the venue of the protest.
"This government cannot suppress the Telangana agitation by arrests. The people are only expressing their democratic wish," TRS MLA T Harish Rao told reporters when he and his colleagues were being taken into custody.
TDP MLAs E Dayakar Rao, senior BJP leader Ch Vidyasagara Rao and others were taken into custody near Basheerbagh.
The Telangana political Joint Action Committee (JAC) Convener M Kodandaram was detained as he was coming out of the JAC office.
"Police have been behaving in a very undemocratic way. They have arrested hundreds of people in entire Telangana," Kodandaram said.
Even policemen in plain-clothes were arresting people, and the vehicles of the MLAs were being checked, he claimed.
TRS president K Chandrasekhar Rao demanded the immediate release of Kodandaram, the MLAs and other Telangana supporters.
Scores of Telangana supporters still reached the Tank Bund, the venue for the 'march' , and shouted slogans in support of the separate statehood and against the Congress government.