Although there has been no official reason given for the detentions, the Pakistan Muslim League-Nawaz (PML-N) says it is an attempt to stifle the party's ability to launch street protests ahead of Nawaz Sharif's return from London.
Pakistani police were detaining scores of supporters of former prime minister Nawaz Sharif, his PML-N party said on Thursday, claiming it was an attempt to prevent them from staging a welcome-home rally upon the ousted leader's return from London.
The Punjab government's caretaker law minister, Shaukat Javed, told Reuters his office had not ordered the detentions.
"Punjab government has not issued any kind of instructions to police for a crackdown against PML-N activists," he said.
A police official who asked not to be identified said more than 100 PML-N workers had been detained.
"We received instructions to take prominent PML-N activists from their areas to avoid a law and order problem," the official told Reuters. It was not clear who had issued the orders.
Meanwhile, authorities in Lahore, the capital city of Punjab province, set up shipping containers and other barricades to block key roads leading to the airport to prevent Nawaz Sharif's supporters from rallying there.
The crackdown on the PML-N – whose leaders have accused the military of attempting to destabilise the party – comes a day before the party founder, ousted prime minister Nawaz Sharif, is due to return to Pakistan – where he faces arrest following his conviction in a corruption case.
Muhammad Mehdi, the party's media coordinator, told Reuters that nearly 500 workers had been detained in a "massive crackdown," including raids on the homes of some of the party's local councillors.
PML-N members have said the crackdown on workers who handle street level organising will make it harder for them to stage rallies and protests on Sharif's return, when he will challenge the verdict and sentence against him.
A Pakistani accountability court on Friday sentenced Sharif in absentia to 10 years in prison for corrupt practices linked to his family's purchase of upscale London flats.
In a televised appeal to supporters from London on Wednesday, Sharif said he was not afraid of prison and asked people to vote for his party in the country's upcoming July 25 vote.
Sharif also used the opportunity to again criticise Pakistan's powerful military, which has ruled the country directly or indirectly for most of its 71-year history, saying Pakistan now has a "state above state".
He has also said the military's intelligence wing, the Inter-Services Intelligence agency, is intimidating his party's candidates to switch loyalties, or to run as independents, ahead of the July 25 polls.
During his term in office, Sharif had also criticised the military's involvement in civilian affairs and its efforts in fighting militants.
Sharif, who is in London caring for his wife who is there for medical treatment, fell out with the military when he returned as prime minister for a third time in 2013, partly because he challenged the military over foreign policy, which the generals traditionally consider their domain.
The run-up to the general election has been marred by accusations that the military is meddling in politics and muzzling the media to help usher cricketer-turned-politician Imran Khan's Pakistan Tehreek-e-Insaf (PTI) into power.
Pakistan’s biggest TV channel, Geo, went off air for several weeks in April and only returned after its executives struck a deal with the military over their coverage of Sharif, two executives told Reuters.
And Pakistan's oldest newspaper Dawn, which has the highest circulation for an English daily, also complains its sellers are being "threatened and coerced by state institutions" following an interview with former Prime Minister Nawaz Sharif in May, where he mentioned the involvement of Pakistani militants in the 2008 Mumbai attacks, which killed 166 people.
#TheNews just informed me they wont publish my regular column tomorrow. A straightforward analysis of Khwaja Asif disqualification. But the thick web of censorship wont let it reach the readers. #PakistanMedia censored as never before. Shall tweet the piece tomorrow. pic.twitter.com/AkytHpkqK6— Syed Talat Hussain (@TalatHussain12) April 29, 2018
Many prominent columnists have also put out statements about their work being censored, often by their own editors.
I had an exclusive interview with PMLN Leader Nawaz Sharif on the eve of his departure from London. He shared his future plans.— Asma Shirazi (@asmashirazi) July 12, 2018
Unfortunately due to unknown circumstances this exclusive interview is not aired.#FaislaAapKa
Khan has denied colluding with the military, but has in the past teased crowds at rallies that a “third umpire” might dismiss PML-N’s then-premier Sharif, widely interpreted as relying on a cricketing metaphor to suggest the army might intervene.
During a press conference earlier this week, military spokesman Major General Asif Ghafoor rejected suspicions that the military was favouring Khan.
“We don’t have a political party. We don’t have a loyalty,” he said.
Ghafoor also dismissed any suggestion the military was forcing Sharif’s supports to switch parties.
DG ISPR’s Press Conference 10july 2018 https://t.co/FSc1Uziahn— Maj Gen Asif Ghafoor (@OfficialDGISPR) July 10, 2018
Dozens of PML-N activists were arrested earlier this week and appeared in court on Wednesday, accused of plotting unrest to coincide with Sharif's return.
A PML-N official told Reuters that police began monitoring his house and the residences of a number of other party activists on Wednesday night.
"I left my house last night and am hiding at a friend's house," Mustafain Shah said.