Pakistan's ruling party chose Thursday its candidate to replace a prime minister ousted by the Supreme Court, but the nominee was immediately hit with an arrest warrant linked to a drug importation scandal in a sign that political turmoil may continue.

Makhdoom Shahabuddin, the outgoing textile minister who is considered a Pakistan People's Party loyalist, filed his nomination papers at parliament, ending speculation that the government may have been planning to defy Tuesday's court ruling against ouster Prime Minister Yousuf Raza Gilani for contempt of court.

The PPP's coalition has a majority in the house. But in an indication his nomination _ and his premiership if elected by lawmakers _ may not be smooth, an anti-narcotics court judge in the northern city of Rawalpindi issued an arrest warrant for Shahabuddin, officials said, citing his alleged role in scandal involving the import of a drug that can be used to make methamphetamine.

The PPP said that a "covering candidate" for the party, lawmaker Raja Pervaiz Ashraf, also filed papers in the event that Shahabuddin was not elected. Horse trading as well as the arrest warrant could complicate the process.

Gilani was dismissed because he refused to initiate a corruption case against President Asif Ali Zardari, the head of the PPP. That was an escalation of a power struggle between the government and activist judges. PPP politicians quickly circulated Shahabuddin's name as a replacement.

The next prime minister will likely also face the same order from the Supreme Court to investigate Zardari, meaning political instability will continue until the government's term ends in March 2013. The Gilani government has been widely criticized for exacerbating or doing nothing to address the massive economic and security challenges in the country. The court has been accused of unfairly targeting the government.

Speaking to reporters after filing his papers, Shahabuddin was asked about the arrest warrant. He replied quoting a line from a poem about not being afraid of "hostile winds."

It's unclear whether the development could derail his nomination. Legal cases are routinely filed against Pakistani politicians by rivals as a means of weakening them. Often, the cases drag on for years, and the politician's career is unhindered. In Shahabuddin's case, any arrest warrant may automatically be dropped if he became prime minister because he has immunity from prosecution.

Shahabuddin was health minister when the scandal broke. Gilani's son has also been linked has also been linked to the case. It revolves around two Pakistani pharmaceutical companies that allegedly used political connections to obtain huge amounts of ephedrine in 2010. They are suspected of diverting it to people in the drug trade who could have used it to make methamphetamines worth billions of dollars. The companies have denied any wrongdoing, as has Gilani's son.

An official at the anti-narcotics force and an official at the law ministry confirmed Judge Shafqatullah Khan had issued the warrant for the arrest of Shahabuddin, as well as Gilani's son, which the force has been pursuing for several months. They said the men would not be able to post bail. The officials spoke on condition of anonymity as they were not authorized to speak to media.

Stability in Pakistan is seen as vital to American goals of withdrawing from Afghanistan in 2014 and long-term victory against international jihadist terrorism. But relations between Washington and Islamabad are strained over a host of issues, including blocked war supply lines to Afghanistan and Pakistan's alleged support for the Afghan Taliban.

The dismissal of Gilani has made it more likely that polls will now be held before next year, possibly as early as November. Elections in Pakistan must be held under a supposedly neutral caretaker government in place three months before polling day, meaning the current government could be dissolved as early as August.

Shahabuddin, 65, comes from a wealthy, landowning family based in the central Pakistani district of Rahim Yar Khan.

His father had served as minister in the cabinets of two Pakistani governments. He also served as minister for finance and health in the current government.