Islamabad: An accountability court on Monday sentenced former Prime Minister Nawaz Sharif to seven years in prison in a fresh corruption conviction.

The Pakistan Muslim League (Nawaz) leader was arrested from the courtroom for having investments beyond his declared assets in Al-Azizia Steel Mills corruption reference. The court acquitted Sharif in the the Flagship Investments case.

Judge Arshad Malik also imposed a $2.5 million fine on Sharif after ruling that Al-Azizia Steel Mills -- a Saudi Arabian firm carrying the name of his son -- belonged to the former Prime Minister and that he was unable to demonstrate how the project was funded, Dawn newspaper reported.

His sons, Hassan and Hussain, were declared absconders. Sharif was expected to appeal against his latest conviction.

Following the verdict announcement, PML-N supporters clashed with security personnel. Tear gas and baton-charge were used to disperse the protesters.

Security around the Judicial Complex in Islamabad was increased ahead of the verdict, with at least 1,400 personnel deployed in and around the court premises. All routes leading to the court were also sealed.

The trial against the Sharifs commenced on September 14, 2017 after Pakistan's anti-corruption body filed three cases relating to the Avenfield, Al-Azizia Steel Mills and Hill Metal Establishment, and offshore companies including Flagship Investment Limited on the Supreme Court's directives in the landmark Panamagate verdict.

Sharif, who denies wrongdoing, was jailed for 10 years in July in Avenfield case -- ownership of four luxury flats in London -- but bailed on appeal when the Islamabad High Court suspended his sentence in September.

His sons are accused in all three references whereas daughter Maryam Nawaz and son-in-law Muhammad Safdar were accused in the Avenfield reference only.