KURNOOL, India (AFP) - A powerful former ally of India's ruling Congress party launched a hunger strike Saturday to protest against plans to carve out a new state in the country's south.

Y.S. Jaganmohan Reddy, who broke away from Congress to start his own party, was greeted by thousands of supporters as he began the fast against the move to split his home state of Andhra Pradesh and create the new state of Telangana.

"We are opposing this unilateral move of the central government to split Andhra Pradesh," he told NDTV news network in Hyderabad, the state capital where many IT giants including Google and Microsoft have offices.

"We will be going to the Supreme Court to protest and challenge the decision of the cabinet. The central government does not want a united Andhra Pradesh."

Reddy, 40, is the son of the late Y.S.R. Reddy, the hugely popular former chief minister of Andhra Pradesh, who died in a helicopter crash in 2009.

The start of his fast came as police fired teargas to disperse a mob that went on a rampage in one district, damaging vehicles, the Press Trust of India reported.

Security has been tightened around homes of Congress leaders, fearing attacks by protestors, police said.

The state would be created out of an impoverished northern area of Andhra Pradesh that its supporters say has been neglected by successive governments.

The national Congress party, led by president Sonia Gandhi, approved the creation of Telangana in July, triggering widespread protests in Andhra Pradesh.

The national cabinet's clearance of the proposal on Thursday sparked fresh demonstrations in the region while three federal ministers tendered their resignations Friday in protest.

The resignations highlighted divisions in an already fractious Congress party that threaten to undermine its performance in national elections due by May 2014.