New Delhi, Jan 24: The entire nation became one in fervently praying for the speedy recovery of Prime Minister Dr. Manmohan Singh who is undergoing a coronary artery bypass surgery today at the All India Institute of Medical Sciences (AIIMS) in Delhi.

A diabetic patient, Dr. Singh was admitted into the hospital for the coronary artery bypass graft surgery. The family members of the Prime Minister are in the capital.

Govind Kaur Dr Singh''s sister said, ""We all are a little concerned. We are praying for his speedy recovery so that he is back to serve the nation soon," said Kaur.

His nephew, Gurdeep Singh wishes him a long life and says that the soft spoken leader would be back soon to serve the country.

"We all are praying that the operation is successful. There are a lot of things that he has to do. We pray that he recovers soon," he said.

Meanwhile, Sikhs across the Punjab are praying at holy Sikh shrines for successful surgery on the Prime Minister.

Sikh priests along with some schools students in Amritsar, offered special Ardas, a Sikh prayer that is done before performing or after undertaking any significant task.

"For the good health and fitness of Prime Minister Manmohan Singh we have read Ardas . We wish that Waheguru put his hand on him and blessed him with long life and good health," said Ranjit Singh, a Sikh priest.

Hundreds of school students in Jalandhar offered prayers during their morning assemblies and wished for Prime Minister''s well being.

"Nothing will happen to him because he is a very honest and truthful man. Our country has developed a lot under his government," said Kulpreet Kaur, a student.

A team of 11 doctors from Asian Heart Institute, Mumbai led by Dr Ramakant Panda, are performing Dr. Singh''s coronary artery bypass graft surgery. The operation is expected to last upto 6- 8 hours.

According to hospital sources, during the surgery, doctors will try to develop an alternate route for the supply of blood by sidelining the blocked part using graft of arteries and vessels derived from other parts of the body.

The coronary artery bypass surgery is performed when arteries get blocked and procedures like angioplasty or medicines fail to clear the blockage.

Surgeons using blood vessels from some other parts of the body will create an alternate route by sidelining the blocked part to carry blood.

Earlier in the week, the Prime Minister had complained of chest pain and then went through a series of tests where some blockages were found in his arteries.

Dr. Singh underwent a cardiac bypass surgery in 1990 in UK, and angioplasty in Delhi in 2004 in which stents were introduced in his arteries.

Grafts, which were used to bypass the diseased vessel on Dr. Singh 18 years ago, have once again started to narrow.

Meanwhile, President Pratibha Patil has assigned the additional charge of the Ministry of Finance to External Affairs Minister Pranab Mukherjee from today onwards till Dr. Singh recovers after undergoing medical treatment. (ANI)