PM Sharif's open heart surgery underway in London

His surgery comes days before his government is set to present its annual budget on Friday

Pakistan Prime Minister Nawaz Sharif is undergoing an open heart surgery in London hospital on Tuesday, his second cardiac procedure in five years.

Dawn reported PML-N's United Kingdom wing president, Zubair Gul, as saying that the surgery began at 12 p.m. Pakistan time and is expected to last anywhere from six to eight hours.

Prime Minister Sharif's surgery comes days before his government is set to present its annual budget on Friday.

Sharif-led government is also under pressure over allegations of his involvement in the Panama Papers leak.

According to Gul, the surgery began at 12 p.m. Pakistan time and is expected to last anywhere from six to eight hours.

Sharif 'was in high spirits when he entered the operation theatre at about 8:00 a.m., his daughter, Maryam, said on her Twitter handle.

The Prime Minister is expected to in the hospital for a week following his surgery.

During his stay at the hospital, the prime minister will be overseeing the affairs of his government from London, the media wing of PM House said earlier.