Pakistan Prime Minister Nawaz Sharif speaks during a joint news conference in Kabul, Afghanistan, May 12.

Pakistan’s Prime Minister Nawaz Sharif is to undergo open heart surgery in London on Tuesday, his second major cardiac medical procedure in five years, his daughter said.

The 66-year-old premier is expected to stay in hospital for around a week after the procedure to recover before traveling home. The details of the operation were not given, but in a series of tweets, Maryam Nawaz Sharif said her father had been experiencing unspecified symptoms.

“Due to certain recent symptoms, doctors made further investigations… The team of cardiologists and cardiac surgeons after thorough examination scans and tests, have decided to go for an open heart surgery,” she tweeted late Friday. “PM in 2011 had a cardiac procedure called ‘Atrial Fibrillation Ablation’, during which certain complications occurred resulting in Perforation of heart which was in turn treated by open heart surgery,” she added.

“The recovery period and hospital stay will be one week and he will travel Insha’Allah (God willing) back to Pak as soon as the doctors allow. Prayers needed.”

Indian Prime Minister Narendra Modi was among those who responded to the tweets, wishing Sharif a speedy recovery and good health. A senior Pakistani government official told AFP, “It may take little over a week for the prime minister to recover and travel back to Pakistan.” The official said Sharif was paying all expenses from his own pocket and “none of the state expenditures are involved”.

Sharif has been under pressure since the so-called Panama Papers leak linked his family to a series of offshore companies. The premier insists his family has done “nothing wrong”, saying the claims had been investigated twice, decades ago, under the tenure former military ruler Pervez Musharraf.

The Panama Papers have whipped up a storm of controversy over offshore wealth, ensnaring political leaders, sports figures and underworld members across the globe in the scandal.

The May 2013 general election saw Sharif take power in a landslide, for the third time. Sharif has a power base rooted in Pakistan’s richest and most populous province, where he is known as the Lion of the Punjab.

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