By Aamir Latif and Islamuddin Sajid

ISLAMABAD / KARACHI, Pakistan (AA) - Police held scores of opposition activists in an overnight crackdown across Pakistan following outrage and widespread protests over the arrest of former Prime Minister Imran Khan on corruption charges Tuesday.

At least three people were killed in clashes between the protesting workers belonging to Khan's party, the Pakistan Tehreek-e-Insaf (PTI), and police, according to officials.

The detainees included Umar Sarfraz Cheema, former governor of the northeastern Punjab province, several lawmakers and second-tier party leaders.

The PTI on Wednesday called for nationwide protests and a shutdown, but distanced itself from violence, calling upon the supporters to remain peaceful and gather outside police headquarters in Islamabad, where Khan is expected to appear before a judge.

According to a government notification, the hearing would take place at a police guest house to avoid any security situation.

While mobile internet and social media platforms remain restricted, schools were shut in many parts of the country.

PTI leader Shah Mahmood Qureshi said the party had no information about Khan's whereabouts.

Khan's lawyer Faisal Chaudhry also told reporters that he had no contact with his client.

The former prime minister was arrested from the Islamabad High Court in one of the several dozen cases filed against him since his ouster last April. His party says the cases are politically motivated.

Since being removed from power after losing a vote of confidence, he has led a campaign for early elections, and accused the US, as well as the country's powerful military, of removing him from office.

Khan was arrested in connection with alleged corruption involving the Al Qadir University Trust.

It is alleged that the cricketer-turned-politician and his wife, Bushra Bibi, received billions of rupees and a large piece of costly land to build the educational institution in return for releasing an amount of £190 million to a property tycoon in 2020.

The amount, equivalent to around PKR 60 billion, was identified and returned to the country by the UK's National Crime Agency (NCA), following a settlement with real estate tycoon Malik Riaz in 2019.

The National Accountability Bureau, Pakistan's anti-corruption body, alleges that Khan’s PTI government struck a deal with Riaz that caused a loss of more than $239 million to the national exchequer, in a quid pro quid arrangement with the businessman.

Khan and his party leaders, however, deny the allegations.