President Pratibha Patil [Images], Vice-President Hamid Ansari, Lok Sabha Speaker Somnath Chatterjee and several other leaders greeted Prime Minister Manmohan Singh [Images], who turned 75 on Wednesday.

The leaders sent flowers and greetings to Dr Singh, who is convalescing at 7 Race Course Road after surgery for a prostate gland problem, a spokesman said.

Congress president and UPA chairperson Sonia Gandhi [Images] called on Dr Singh.

Russian President Vladimir Putin [Images] also called up the prime minister on his birthday.

Dr Singh, born in 1932, does not celebrate his birthdays. The prime minister is slated to release a book later in the day.