Mr Reddy has yet to finalise his line up of state ministers

Mr Reddy, of the Congress party, crushed the incumbent Chandrababu Naidu of the Telugu Desam.

Mr Reddy immediately announced he would grant free electricity to small farmers and poor families.

His state election victory, declared on Tuesday, was echoed in a massive swing to Congress in the general election.

'People friendly'

An estimated 30,000 supporters came from all over the state to witness Mr Reddy take the oath of office at the sprawling Lal Bahadur stadium.

For people who could not make it inside the stadium, organisers installed giant screens outside.

Chandrababu Naidu, a BJP ally, was regarded as an IT guru

The BBC's Omer Farooq in Hyderabad says the oath was taken at exactly 1339 local time (0909 GMT) - an auspicious time directed by astrologers.

Mr Reddy took the oath alone as his ministers cannot be finalised until the central Congress leadership decides its post-election strategy.

Mr Reddy immediately ordered free electricity for small farmers and families below the poverty line - a pledge other politicians in the past have made but failed to implement because of a lack of funding.

Mr Reddy said all his policies would have "a people-friendly orientation".

Mr Naidu, an ally of the outgoing Bharatiya Janata Party, was regarded as an IT guru who turned Hyderabad into a cyber centre.