Indian Prime Minister Manmohan Singh will undergo heart bypass surgery over the weekend, officials say, after blockages were found in his arteries.
Indian Prime Minister Manmohan Singh has gone into hospital in Delhi for heart bypass surgery, officials say.
The 76-year-old leader will enter hospital in Delhi on Friday for the surgery on Saturday, a spokesman said.
A team of six to eight surgeons will operate on the 76-year-old leader on Saturday morning, after doctors found two blockages in his arteries.
Mr Singh previously had bypass surgery in the UK in 1990.
Mr Singh previously had bypass surgery in 1990 and an angioplasty in 2004.
The new surgery will raise questions about Mr Singh's participation in the upcoming general elections, which must be held by May.
The ruling Congress Party says Mr Singh will still lead the party in the forthcoming general election which is due by May.
Foreign Minister Pranab Mukherjee is likely to take charge of prime ministerial meetings while Mr Singh recovers from the operation, reports say.
Mr Singh underwent tests earlier this week after he complained of chest pains.
Mr Singh underwent tests earlier this week after he complained of chest pains.
He will undergo "coronary artery bypass graft surgery" performed by a team of doctors from the All India Institute of Medical Sciences, India's top state-run hospital, and the Asian Heart Institute in Mumbai, a government official said.
He will undergo "coronary artery bypass graft surgery" performed by doctors from the All India Institute of Medical Sciences, India's top state-run hospital, and the Asian Heart Institute in Mumbai.
Doctors say that there is "very little risk" associated with Mr Singh's surgery and that the prime minister should be fit to resume normal duties in three to four weeks.
Gandhi dynasty
Gandhi dynasty
Doctors say that there is "very little risk" associated with Mr Singh's surgery and that the prime minister should be fit to resume normal duties in "three to four weeks".
But the BBC's Jill McGivering says this is not a good time for the prime minister to be removed from the political fray, given the tense relations with Pakistan in the wake of the Mumbai attacks. Will Rahul Gandhi emerge as a successor to Mr Singh?
But the BBC's Jill McGivering says this is not a good time for the prime minister to be removed from the political fray given the tense relations with Pakistan in the wake of the Mumbai attacks.
Congress has so far dismissed concerns that Mr Singh's health would interfere with its current election campaign.
Will Rahul Gandhi emerge as a successor to Mr Singh?
But there has been widespread speculation that party chief Sonia Gandhi has been lining up her son, Rahul Gandhi, heir to India's powerful Gandhi dynasty, as the country's next prime minister.
She adds that health concerns will also certainly not help when it comes to defending in the election campaign economic policies that have been less sweeping and less successful than hoped.
Mr Singh has largely been in good health since he was sworn in as prime minister in May 2004, but he recently underwent prostate surgery and has also had cataract treatment.
Though Congress party leaders have been saying that Mr Singh will be heading the party into the next elections, there have been reports that Rahul Gandhi, heir to India's powerful Gandhi family, is emerging as a successor.
Mr Singh, who studied economics at Cambridge and Oxford, became India's finance minister in 1991 when the country was plunging into bankruptcy, and is widely regarded as the architect of the country's economic reform programme.
It is not clear whether Mr Singh will be able to campaign intensively after his surgery, but the economist-politician has never been used by the party to woo voters in a big way.
The quietly spoken economist-politician is also seen as the cleanest politician in India, a subject dear to voters' hearts.
The Gandhi family and regional politicians will continue to be more important, analysts say.
Government officials said that Foreign Minister Pranab Mukherjee will take charge of cabinet meetings during the prime minister's absence.
Apart from Mr Singh's heart bypass in 1990 he has also undergone wrist surgery, prostate gland surgery and a cataract removal procedure, officials said.
Mr Singh - the first prime minister from the Sikh community - has been heading the government since 2004.
He is widely regarded as the architect of the country's economic reform programme.
An academic-turned-civil servant who studied economics at Cambridge and Oxford, Mr Singh became India's finance minister in 1991 when the country was plunging into bankruptcy.
He is also widely regarded as the cleanest politician in India, a subject dear to voters' hearts.
