Indian Prime Minister Manmohan Singh will undergo coronary artery bypass surgery on Saturday only months before he is due to lead the ruling Congress party into general elections.
Any doubts about Mr Singh's health could undermine his re-election campaign, coming just as reports surface that Rahul Gandhi, heir to one of India's most powerful family dynasties, was emerging as his successor to lead the Congress party.
The 76-year-old leader will be admitted to hospital today, the prime minister's office said.
Foreign Minister Pranab Mukherjee could take over prime ministerial responsibilities while Mr Singh was recovering from the surgery, a foreign ministry official said.
A general election is due by May this year and Mr Singh was expected to continue as prime minister if the Congress coalition wins. The main battle is between the Congress-led government and a coalition led by the Hindu-nationalist Bharatiya Janata Party.
The surgery could mean that Singh will not be able to carry out full vote campaigning. But the soft-spoken economist was never central to Congress's campaigning plans, analysts said.
Mr Singh underwent bypass surgery in 1990 in the United Kingdom. He also underwent wrist surgery in 2006, a prostate gland surgery and a cataract removal procedure last year, officials said.
Reuters