Former US president Bill Clinton has undergone heart surgery in a New York hospital following complaints of chest pain.

One of his advisors said Mr Clinton was in good spirits after the operation. Two stents - tubes placed in coronary arteries to keep them open - were placed. The 63-year-old underwent a quadruple bypass operation in 2004.

Mr Clinton is currently the special United Nations envoy for Haiti. He is expected to resume his duties as soon as he has recovered from the operation.