LONDON: Prime Minister Nawaz Sharif's open-heart surgery has been performed successfully in London, and he has been shifted to the Intensive Care Unit (ICU), confirmed the premier's daughter on Tuesday.

Maryam had added after the surgery concluded that the prime minister will be shifted to the ICU with in the next hour. In a separate tweet she also thanked the people for their prayers and well wishes.

The surgery was started earlier in the day at 8am UK time and lasted more then four hours.

"PM's surgery started at 8am UK time. Spoke to him earlier, he was in high spirits," Maryam tweeted earlier.

"All arteries successfully grafted," Maryam said, adding that surgery may take another 60 to 90 minutes to conclude.

Earlier, Maryam had said the surgery was progressing fine.

Information Minister Pervaiz Rasheed said prayers across the world were held for the premier's well being and health.

"Everyone has prayed for him, Muslims prayed in mosques, Hindus in temples and Christians in churches."

Zubair Gul, president of PML-N's United Kingdom chapter had said the surgery, which began at 12pm Pakistan time, is expected to last anywhere from six to eight hours.

However, there is a great deal of secrecy surrounding the PM's surgery and it is not known which hospital he has been admitted to. The premier could not be found at the Royal Brompton Hospital in Chelsea where he previously received treatment, and is presumed to have left his home without detection.

Members of the premier's security detail have allegedly been posted at various hospitals to throw reporters off the trail.

The prime minister is expected to be in the hospital for a week following his surgery. During his stay at the hospital, the premier will be overseeing the affairs of his government from London, the media wing of PM House said earlier.

On Monday, the PM addressed an economic meeting and signing off on budget proposals for the upcoming fiscal year.

Prayers and goat sacrifices ahead of PM's surgery

PML-N supporters have offered prayers and sacrificed animals ahead of Prime Minister Nawaz Sharif's surgery.

The party's social media pages are filled with well wishes from people across the globe, and picture of supporters indulging in goat sacrifices.

PML-N's official pages also had supporters sending their best wishes for the PM.

The premier also thanked the nation for their prayers a day before his surgery was scheduled.

The need for the surgery arose after the premier went through a cardiac procedure called Atrial Fibrillation Ablation in 2011, "during which certain complications occurred resulting in perforation of heart", Maryam Nawaz earlier told the media.

"After some recent symptoms, a team of cardiologists and cardiac surgeons carried out some scans and tests, following which they decided to go for an open-heart surgery," she said.

World leaders, also conveyed their wishes for the PM's quick recovery in days leading up to his surgery.

Prime Minister Nawaz Sharif telephoned his Indian counterpart Narendra Modi on Monday to express his gratitude for the good wishes for his recovery before being wheeled in for his heart surgery, Radio Pakistan reported.