Islamabad, Pakistan - Former Pakistani Prime Minister Nawaz Sharif and his daughter Maryam have been taken into custody on arrival in the eastern city of Lahore, party officials said.
The Sharifs arrived in Pakistan's second city from the UK on Friday evening, submitting themselves for arrest after they were convicted by an anti-corruption court last week, TV footage showed.
"They have [been arrested] and have been taken to Adiala [jail]," Marriyum Aurangzeb, spokesperson for Sharif's PML-N party, said.
The arrest will be a blow to the PML-N, which is contesting a July 25 general election as the incumbent party, but alleges that it has been the victim of "political engineering" by its opponents during the campaign.
In a landmark verdict, the Sharifs were convicted by an anti-corruption court for not being able to prove a legitimate source for funds used to buy a set of upscale London apartments.
Sharif, a three-time prime minister, was sentenced to 10 years in prison and a $10.5m fine, while his daughter was given a seven-year sentence and $2.6m fine.
Maryam Nawaz's husband, Muhammad Safdar, was also sentenced to a year in jail and was arrested last week. He is also held in Adiala jail in Rawalpindi, about 240km northwest of Lahore.
The elder Sharif had been dismissed as prime minister last July, after the Supreme Court ruled that he had lied on a parliamentary wealth declaration. Sharif denies all charges and says they are politically motivated.
Since his dismissal, he has led a series of rallies across the country, pointing the finger of blame at Pakistan's powerful military, which has ruled it for roughly half of its 70-year history and still largely controls security and foreign policy.
Election rallies targeted
Thousands rallied in the eastern city of Lahore, Sharif's political heartland, to welcome him and his daughter back to the country, braving roadblocks and riot police. Scores of PML-N workers were arrested in the run-up to Sharifs' arrival, the party said.
Mobile phone networks were also shut down in the city, with authorities saying the disruption was meant to counter the threat of remote-controlled bombs.
Senior PML-N leaders, including Nawaz's brother Shehbaz, led rallies to the airport from across the Punjab province that is their political base. Supporters waved flags and called for the judiciary "to give honour to the vote", a popular campaign slogan.
Some cars in the rallies carried plastic or stuffed tigers attached to their rooftops, a nod to the PML-N's election symbol.
The Sharifs had been visiting the UK capital of London, where Nawaz's wife Kulsoom is undergoing treatment for cancer, and had been unresponsive for several weeks, according to Maryam Nawaz.
Speaking to the press from an airport lounge in Abu Dhabi, a defiant Sharif said he was submitting himself for arrest as a mark of protest.
"There are [about] 10 days to the election, is this how elections are held?" he said. "If the elections have no credibility, then who will accept the results?"
Sharif had previously been jailed for several months after he was deposed in a military coup in 1999, before being allowed to fly to Jeddah to live in exile. He returned to Pakistan in 2008 to lead his party in a general election, before himself ascending back to power after the 2013 polls.
Asad Hashim is Al Jazeera's Digital Correspondent in Pakistan. He tweets @AsadHashim