Prime Minister Manmohan Singh said on Saturday that even though he was not an aspirant for the top political post in the country, it was a 'great challenge, honour and opportunity' to occupy the chair.

''It is a great honour and privilege to be entrusted with this onerous responsibility,'' Singh said when asked whether he considered it a burden or was enjoying being prime minister.

Addressing his first press conference after becoming prime minister over three months ago, Singh said,  ''Of course, I was not an aspirant for the post. But having been in office for over 100 days, I consider it as an honour, challenge and opportunity.''