Pittsburgh, Sep 26 - Prime Minister Manmohan Singh, who turns 77 Saturday, has vowed to dedicate himself to the nation, saying people's renewal of confidence in him after five years in office was a debt he could never pay off.

'I am grateful to people of India for giving me opportunity to serve the nation,' he told reporters here Friday. 'I completed five years. Again, they renewed their confidence in me that is the debt I can never pay off.'

'I can only make an effort to repay it by dedicating my self to the nation and serve it in best of my ability,' Manmohan Singh said when asked to give a message on his birthday.

Born on Sep 26, 1932, in Gah village in what is now known as Chakwal district in Punjab, Pakistan, the prime minister will be celebrating his birthday in Geneva on way to New Delhi after attending the G-20 summit here.