TEHRAN (Press Shia) – Pakistan's ruling party plans to appoint the brother of ousted Prime Minister Nawaz Sharif as his successor to fight the 2018 general elections, local media reported on Saturday, but will first have to appoint an interim prime minister.

Shahbaz Sharif, 65, the chief minister of the vast Punjab province that accounts for more than half of Pakistan's 190 million people, will need to be first elected to the national assembly before he can take over as leader of the country, according to Reuters.

Nawaz Sharif's resignation on Friday has plunged the nuclear-armed nation into political turmoil after several years of relative stability. Sharif quit after he was disqualified by the Supreme Court over undeclared assets.

The court has also ordered a criminal investigation into Sharif, 67, and his family.

Sharif has always denied any wrongdoing and his toppling has rekindled concerns about Pakistan's democracy after a member of his Pakistan Muslim League-Nawaz (PML-N) party hinted that elements of the powerful military were in some way involved.

"We know very well what the crime of Nawaz Sharif and the Muslim League is. What do we ask for? We ask for civilian supremacy in Pakistan," Railways Minister Khawaja Saad Rafiq told a news briefing.

Questioned further, however, Rafiq would not name the military as a whole.

The army has not commented on Sharif's removal, or allegations they were involved. In the past, the army has dismissed claims they are behind Supreme Court's push against Sharif.

Sharif's PML-N party is due to meet on Saturday and will likely appoint a short-term leader to fill the vacuum until Sharif's younger brother becomes an elected lawmaker, according to the English-language News and Dawn newspapers.

"This decision was taken here at the PM House on Friday," the News reported on Saturday.

Among possible allies to replace Sharif in the short term are members of his outgoing cabinet including Defense Minister Asif Khawaja, Planning Minister Ahsan Iqbal and Petroleum Minister Shahid Abbasi.

If elected, the interim leader would be in power for at least 45 days until Shahbaz steps down as the head of the Punjab government, and contests a by-election to the national assembly.

Rafiq, the railways minister, told Geo TV late on Friday that it was not yet decided if the interim leader would be in power for a 45-day period or until the next general election in early August 2018.

Whoever replaces Sharif will have to tackle Pakistan's worsening ties with the United States, frayed relations with India, and persistent attacks by militants.

The state of the economy – which is growing at its fastest pace in a decade – has also begun to concern economists, who are warning an over-valued currency is hurting exports and urge action over a ballooning current account deficit.

Shahbaz Sharif has been in charge of Punjab since 2008, building a reputation as a competent administrator focused on building infrastructure. He also has better relations with the military than his brother.