In a pre-dawn action, police in Telangana detained state Congress Working President Revanth Reddy ahead of Chief Minister K. Chandrashekhar Rao's election rally in Vikarabad district.
Police said he was taken into preventive custody from his residence at Kodangal at 3 a.m. to prevent any untoward incident during Rao's rally in Kosgi. He was shifted to an undisclosed location.
Reddy, who quit the Telugu Desam Party (TDP) to join the Congress earlier this year, represented Kodangal in the dissolved Assembly.
His detention came in view of Reddy's threat to disrupt the Telangana Rashtra Samithi (TRS) chief's rally. He had called for a shutdown to protest police raids at his house last week.
The Election Commission had also issued a notice to Reddy over his threat. A police officer said a case was booked against Revanth Reddy on a complaint by the Electoral Officer.
Tension prevailed in Kodangal following Reddy's detention. The police have already imposed prohibitory orders in the town to prevent any untoward incident.
Reddy's wife condemned the police high-handedness and wanted to know his whereabouts. She lodged a complaint with the Returning Officer.
Congress workers at Jadcherla in Mahabubnagar district staged a protest, demanding immediate release of Revanth. One of the protestors attempted self-immolation.
A Congress leader filed a habeas corpus petition in Hyderabad High Court and the same is expected to come up for hearing later in the day.
Congress spokesman Manish Tiwari told reporters in Hyderabad that they will lodge a complaint with the Election Commission.
State Congress chief Uttam Kumar Reddy alleged that the police arrested Revanth at the behest of the Chief Minister. He said the TRS leader was misusing his power and the election authorities were biased.
Senior Congress leader S. Jaipal Reddy condemned the manner in which police arrested Revanth. He said the fear of election defeat had gripped KCR.
State Chief Electoral Officer Rajat Kumar, however, denied the allegations that they were biased. He said they treat all political parties equally.
Elections to the 119-member Telangana Assembly are scheduled for December 7.
(With inputs from agencies.)