MILAN (Reuters) - Italian surgeons began a four-hour heart operation on former prime minister Silvio Berlusconi on Tuesday (June 14) to replace a defective aortic valve, a hospital statement said.

The surgery started at 8am local time, the statement added.

The 79-year-old centre-right leader and media mogul was admitted to hospital last week suffering from what his doctors called a cardiac deficiency.

In a post on Facebook, Mr Berlusconi wrote on Monday: "Naturally I am worried, but I have been very much consoled by the outpour of affection and support that have come from many parts, including from so-called political enemies."