New Delhi, Jan. 25 : Residents of Delhi on Sunday joined the rest of the nation in expressing concern over Prime Minister Manmohan Singh''s health and wished him speedy recovery after he had undergone a sucessful artery bypass surgery.

Ajay Gupta, a city resident, said the country needs Prime Minister Manmohan Singh.

"We wish him (Prime Minister Manmohan Singh) all the success and a good speedy recovery. We really hope that he is back to his job as soon as possible because he is one of the ablest men that we have. And we really need him at this hour," Gupta said.

Others like Vishwa Devi said that they would join the nation to offer prayers for the good health of the Prime Minister.

"We shall pray to God for his speedy recovery, all our well wishes are with him," said Devi.

No acting Prime Minister has been named while Singh is in hospital, raising concerns about leaving the nuclear-armed country rudderless while the 76-year-old leader recovers.

Until Manmohan Singh recovers, Foreign Minister Pranab Mukherjee has been assigned the task of overseeing certain prime ministerial responsibilities, as well as the finance portfolio.

But the lack of a clear deputy has led to speculation that the ruling Congress party did not want to give Mukherjee a public endorsement as acting prime minister, and overshadow other candidates within Congress battling to be Singh''s successor.

Singh''s operation came just as his Congress party prepares its campaign for a general election by May. The main battle is between the Congress-led government and a coalition led by the Bharatiya Janata Party.

Despite his illness, some analysts say there is no clear alternative to Singh, a soft-spoken economist seen in India as a respected elder statesman.

Singh underwent bypass surgery in 1990 in Britain. He also underwent wrist surgery in 2006, a prostate gland surgery and a cataract removal procedure last year, officials said.

A team of doctors from the All India Institute of Medical Sciences (AIIMS) of New Delhi and the Asian Heart Institute of Mumbai, conducted coronary artery bypass surgery upon Singh.

In the periodical health bulletin issued by AIIMS, it was mentioned that Singh''s condition was stable.

Singh will be in hospital for at least a week and may be able to return to work in a month, doctors who operated upon him have said.

Pakistan President Asif Ali Zardari and Prime Minister Yousaf Raza Gilani have sent bouquets to Prime Minister Manmohan Singh wishing him early recovery. (ANI)