Y S Jagan Mohan Reddy was Thursday sworn in as the chief minister of Andhra Pradesh and on his first day in office, he ordered enhancement of old age pension for the poor -- one of his party's nine pre-poll promises, "Navaratnalu".

Governor E S L Narasimhan administered the oath of office and secrecy to the 46-year-old leader, whose party won 151 seats in the 175-member strong state assembly.

Reddy took the oath in Telugu at 12.23 pm amid thunderous cheers by scores of party leaders and workers in a brief ceremony at the IGMC Stadium in Vijayawada.

His council of ministers is expected to be sworn in on June 7.

"For all the hardship I faced for nine years... The 3,648 km 'padayatra' (foot march) I undertook... You all blessed me so much that you gave me a victory as big as the sky. I have seen your troubles, listened to your grievances. I assure you that I am here to address all of them," an emotional Reddy said after taking oath.

After the swearing-in ceremony, Reddy signed a file for enhancing the monthly old age pension from Rs 1,000 to Rs 3,000 for the poor.

The chief minister also announced appointment of four lakh village volunteers (educated unemployed youth) by August 15 this year to work in the proposed 'Grama Sachivalayams' (village secretariats).

Each volunteer would be paid a monthly honorarium of Rs 5,000 till they find a better job, Reddy said.

"Navaratnalu" also includes promises of supporting farmers with a grant of Rs 12,500 per annum; phased implementation of liquor ban and implementation of 'Aaroygyasri' scheme, under which financial assistance of Rs 10,000 will be given to patients suffering from serious diseases.

Reddy also assured of a total clean up of the state administration to root out corruption through "revolutionary and transparent" governance.

Any existing contract for development projects would be scrapped if corruption is detected, the YSRCP chief said.

He was alluding to the Polavaram project, capital city Amaravati and other major works that stoked controversies during the previous Chandrababu Naidu-led government's regime.

A dedicated call centre would be opened in the Chief Minister's Office on Independence Day to receive complaints, if any, on corruption at any level, Reddy announced.

"All government benefits under different welfare schemes will henceforth be delivered at the doorsteps of beneficiaries by the village volunteers," he said.

"Any new application seeking welfare benefits will be disposed of within 72 hours," he added.

The chief minister also promised that there would be "no discrimination of any kind" in disbursal of welfare benefits.

Just before Reddy's address, Christian pastors, Muslim maulvis and Hindu priests recited prayers and blessed him.

He is the second chief minister of the state post its bifurcation in 2014.

Vedic scholars from the Tirumala Tirupati Devasthanams blessed the YSRC president at his residence here ahead of the oath-taking ceremony.

Reddy reached the stadium and went round the galleries in an open-top jeep to greet thousands of people who had come to witness the event.

Telangana Chief Minister K Chandrasekhar Rao, DMK chief M K Stalin and Puducherry Health Minister Malladi Krishna Rao were the special guests at the swearing-in ceremony.

Telangana Deputy Chief Minister Mahmood Ali, Assembly Speaker Pocharam Srinivasa Reddy, minister Talasani Srinivasa Yadav also attended the ceremony.

Reddy's mother and YSRC honorary president Y S Vijayamma, his wife Bharati and sister Sharmila and family members were seated on the dais.

Maverick film director Ram Gopal Varma, who normally stays away from politics, specially attended Reddy's swearing-in ceremony.

Naidu, who was invited by Reddy over phone, decided to stay away from the function.

The YSR Congress also decimated Naidu-led Telugu Desam Party in the recent general election, winning 22 of the 25 Lok Sabha seats in the state.