Authorities in Pakistan swiftly arrested former Prime Minister Nawaz Sharif and his daughter and political heir, Maryam, shortly after the two landed in the eastern city of Lahore on a commercial flight from Britain on Friday.
The two were to be flown in a special aircraft to the main jail in the garrison city of Rawalpindi, officials said.
The arrest was made in connection with a recent verdict from an anti-corruption court. Sharif and his daughter were sentenced in absentia to 10 years and seven years in prison, respectively, for failing to explain how they acquired expensive properties in London.
Legal experts say that without surrendering to authorities, Sharif would have not been eligible to appeal the verdict.
Meanwhile, tens of thousands of supporters and leaders of Sharif's Pakistan Muslim League-Nawaz (PML-N) party flooded the streets in Lahore on Friday in anticipation of the arrest of their leader. They also clashed with riot police in parts of the capital of the country's most populous province of Punjab.
The provincial government had beefed up security ahead of Sharif's arrival in Lahore, and detained scores of protesters in their bid to deter massive gatherings near the airport, officials said.
Sharif has denounced the verdict as politically motivated. He has accused a covert military-judiciary alliance of trying to keep him out of politics and of undermining the integrity of his PML-N party.
PML-N candidates have also alleged Pakistan's intelligence agency, ISI, is pressuring them to switch loyalties and contest the July 25 polls as independents.
A spokesman for Pakistan's Independent Election Commission, which oversees the polls, urged candidates Thursday to register complaints if they are being intimidated.
WATCH: Pakistan's Thrice Elected, Ousted Nawaz Sharif, Daughter, Jailed
The army has strongly rejected charges it is meddling in the democratic process, or muzzling the media, to rig the polls in favor of the Pakistan Tehreek-e-Insaf (PTI) party, led by sports celebrity Imran Khan.
"We don't have a political party. We don't have a loyalty," the army spokesman said earlier this week.
Major-General Asif Ghafoor also dismissed suggestions his institution is forcing Sharif's supporters to switch parties.
He said the election commission has requested that the army assist in organizing a "fair and free" election on July 25, and more than 370,000 troops are being deployed at polling stations around Pakistan to achieve the objective.
Khan, who has been leading legal battles and demanding Sharif's accountability through street protests, denies his party is colluding with the military.