Hundreds of people from all walks of life on Saturday thronged gurudwaras across the nation to offer special prayers for Prime Minister Manmohan Singh [Images], who is undergoing coronary by-pass surgery for the removal of blockages in his heart vessels.

Prayers were being offered in gurudwaras in Delhi [Images], Kolkata, Amritsar [Images] and Guwahati for the successful operation of the prime minister.

In Amritsar, the prime minister's brother and other family members offered prayers at the Golden Temple [Images] for the success of his surgery.

Surjit Singh Kohli, the prime minister's brother, said they were leaving for Delhi to be with Singh after the surgery. "We hope to be with the prime minister when his surgery is over," Kohli told PTI over the phone from Amritsar.

He said they had offered 'Ardas' (prayers) at the Golden Temple for success of the surgery and Dr Singh's health.

"We are also aware that millions of our countrymen and Punjabis the world over are praying for his good health," he said.

Local Congress leaders also held prayers early this morning at the Golden Temple for Singh's good health.

Both the prime minister's sisters -- Naveen Kaur and Preetam Kaur -- also joined a mass prayer at a gurudwara in Kolkata for the successful heart surgery of their brother.

The two sisters, accompanied by senior priests at Taratala Gurudwara in South Kolkata, offered prayers at 9 am.

People also offered special prayers for Singh at a Gurudwara in Guwahati in Assam, which the prime minister represents in Rajya Sabha.

"All citizens of Guwahati irrespective of their faiths are praying for the prime minister's health. We pray to God that he recovers soon and resumes office," a priest, leading special prayers in the Gurudwara, said.

Prayers were also held in the national capital for the speedy recovery of the 76-year-old leader.

"Many people offered prayers at the Bangla Sahib Gurudwara (near Connaught Place), the Sisganj Sahib Gurudwara (in Chandni Chowk) and Gurudwara Gurunanak Pio (at GT Karnal Road), for the prime minister's successful operation and his speedy recovery," Delhi Sikh Gurudwara Management Committee President Paramjeet Singh Sarna, told PTI.

Devotees of all age groups in Delhi gathered to offer 'Sangat' (mass prayer) and 'Ardaas' (request) early in the morning at nearby gurudwaras.

The prime minister was wheeled into the operation theatre of the All India Institute of Medical Sciences at 5.30 am on Saturday while the bypass surgery started at 7.15 am.

An all-faith prayer meeting was also held at atheGarcha Gurudwara in South Kolkata at the instance of the West Bengal Pradesh Congress Committee.

WBPCC acting president Pradip Bhattacharya, who took part in the prayer along with WBPCC secretary Tulsi Mukherjee, told PTI that members from different religions prayed for the successful operation of the prime minister.

"We also prayed to the almighty that the Prime Minister's operation ends successfully and he recovers quickly to take charge of the country," Bhattacharya said.