Authorities had placed Lahore in a lock down with thousands of police deployed to the city and shipping containers placed along main roads to block PML-N supporters from moving towards the airport where Nawaz Sharif and his daughter had landed.
Pakistani accountability officials have arrested ousted prime minister Nawaz Sharif and his daughter Maryam on their return to the country from London on Friday in a high-stakes gamble to galvanise their beleaguered party ahead of a July 25 general election.
Sharif was ordered jailed in a case stemming from 2016 Panama Papers revelations that showed they owned the apartments through off-shore companies. Maryam was convicted for concealing ownership of the apartments.
They both deny wrongdoing and said they would appeal the court's decision.
In a video message posted on his daughter's Twitter account, Sharif said "I know I have been sentenced to 10 years in prison, and would be taken straight away to jail. I'm doing all this for the Pakistani nation."
Nawaz and Maryam's return could shake up an election race marred by claims Pakistan's powerful military was skewing the contest in favour of ex-cricket hero Imran Khan.
On Friday afternoon, thousands of police had been deployed in the central city of Lahore and shipping containers placed along main roads, to block protesters from moving towards the airport, where Sharif had arrived.
Mobile phone service was cut off by mid-afternoon, as Sharif's brother, Shehbaz, led around 10,000 supporters of his Pakistan Muslim League-Nawaz (PML-N) on a march toward the city centre in defiance of a citywide ban on public gatherings, according to a Reuters witness.
Nawaz Sharif decried the tactics ordered by the caretaker government that took over in June ahead of the general election, as Pakistan's constitution requires.
"What credibility will these elections have when the government is taking such a drastic action against our people and this crackdown is taking place all over the country?" Sharif told Reuters at the airport in Abu Dhabi as he waited for a connecting flight to Lahore.
Pakistan's third major political movement, the Pakistan Peoples Party, joined the criticism of the crackdown, with its prime ministerial candidate Bilawal Bhutto Zardari questioning why Sharif's supporters would be arrested and prevented from gathering.
Understand the legal grounds for arrest of MNS after NAB conviction but on what grounds are workers and leaders being arrested? Why is Lahore under siege ? Right to peacful protest is fundamental for democracy.— BilawalBhuttoZardari (@BBhuttoZardari) July 13, 2018
"Why is Lahore under siege? Right to peaceful protest is fundamental for democracy," tweeted Bhutto Zardari, the son of two-time prime minister Benazir Bhutto, who was assassinated at a political rally in 2007.
Imran Khan "quietly confident" of win
Imran Khan said he was "quietly confident" of victory in a general election this month and that as prime minister, he would drive an anti-corruption and anti-poverty campaign in the south Asian nation.
"What Pakistan has to do is follow China's example where they lift people out of poverty," Khan said in the interview in a private jet after a long night of campaigning in Punjab province.
"And actually we have meetings with the Chinese on all the steps they took to reduce poverty."
Khan's party has pulled ahead of others in one opinion poll and he said of his chances in the election: "I'm quietly confident that this time we'll do it. I am hopeful, I am confident, but still, the match is not over until the last ball is bowled."
Addressing an election rally a day earlier, Khan had called PML-N supporters who wanted to receive their leaders "donkeys."
Sharif alleges the military is aiding a "judicial witchhunt" against him and his PML-N party. The party's past five years in power has been punctuated by the civil-military discord that has plagued Pakistan since its inception.
"Nawaz really believes this is about democracy and his legacy," Musadik Malik, Sharif ally and former PML-N cabinet minister, told Reuters.
"That is why he is willing to lose 10 years of his life over this."
Sharif's PML-N expects a groundswell of support as he returns from London, where his wife Kulsoom is critically ill and undergoing cancer treatment.
To prevent PML-N workers staging a hero's welcome on the streets, authorities said they will arrest the father and daughter upon landing and transport them to the capital Islamabad by helicopter, local media reported.
Party officials say the police have started a crackdown against them, detaining hundreds of workers in the early hours on Friday.
Recent opinion polls suggest PML-N has lost its lead nationally to the Pakistan Tehreek-e-Insaf (PTI) party of arch-rival Khan, whose anti-corruption message has resonated with many Pakistanis.
Khan has painted Sharif as a "criminal" who has looted the state for decades, and welcomes his prison term as overdue accountability.
Sharif was ordered jailed after failing to explain how the family acquired the London flats in a case stemming from 2016 Panama Papers revelations that showed they owned the apartments through off-shore companies. Maryam was convicted for concealing ownership of the apartments. The both deny wrongdoing.
Sharif, 68, has cast himself as a defender of democracy, a far cry from the start of his political life when he was the protege of military dictator General Zia ul Haq and had his career nurtured by the military dictator in the 1980s.
He was elected prime minister in 1990 and was ousted by then-president Ghulam Ishaq Khan in 1993.
A second stint in power that began in 1997 was ended by a military coup in October 1999, prompting a period in jail for Sharif and years in exile in London. When he returned to power in 2013, he clashed with the military over how to deal with militancy and his desire for friendlier relations with India.
After the Supreme Court disqualified Sharif in July 2017 for not declaring a small source of income which he denied receiving, he toured the country urging voters to protect the "sanctity of the vote."
"Despite seeing the bars of prison in front of my eyes, I am going to Pakistan," Sharif told Pakistani journalists this week in London, where he vowed to reassert "civilian supremacy."
The opposition Pakistan People Party (PPP) has also alleged "pre-poll rigging" this week, but did not specifically name the armed forces.
The military, which has ruled Pakistan for about half its history since 1947, has denied interfering in modern-day politics. It plans to place 371,000 soldiers around polling stations so there can a "free and fair" elections, it added.
Sharif's return comes at a time of dwindling fortunes for his party, which one year ago was considered a runaway favourite to retain power.
After the Supreme Court ousted Sharif last July, the courts barred him from heading the PML-N party he founded. His brother Shehbaz became PML-N's president, but Sharif remains the power behind the throne.
Since then, a host of his allies have been either disqualified by the courts, or face corruption cases. Many PML-N lawmakers have also defected to Khan's party.
PML-N has also been riven by internal divisions. Sections of the party oppose Sharif's combative approach against the army and fear it will turn off voters in a deeply conservative and patriotic Muslim nation of 208 million people.
The kind of reception Sharif receives on the streets of Lahore will be viewed carefully in Pakistan, where political popularity is often measured by the size of rallies that politicians can attract.
PML-N leaders say authorities have began a crackdown against union council leaders, the street-level party workers who bring out people on the streets.
"Those who think they can scare us ... open your ears and hear this: we are winning this election," Shehbaz Sharif told reporters in Lahore on Thursday.