Islamabad (AFP) - Pakistan’s political turmoil intensified late Wednesday with violent nationwide protests swelling and the government deploying the military as former prime minister Imran Khan was remanded in custody for eight days on fresh corruption charges following his dramatic detention.

Khan was arrested Tuesday during a routine hearing in the capital Islamabad and whisked away to an unknown location overnight before appearing behind closed doors in a specially convened anti-graft court at police headquarters.

The upheaval, including mass arrests of protesters, follows months of political crisis during which Khan, who was ousted in April last year, has waged an unprecedented campaign against the country’s powerful military.

“If they think that the arrest of Imran Khan will demoralise us, then they are hugely mistaken,” said supporter Niaz Ali in Peshawar, where several monuments and government buildings have been torched.

“We stand with Imran Khan and will support him till death.”

The cabinet Wednesday approved deployment of the army in two provinces and the capital to restore peace, a statement from Prime Minister Shehbaz Sharif’s office said.

In Pakistan’s largest city Karachi, security forces fired tear gas to disperse supporters of Khan’s Pakistan Tehreek-e-Insaf party, while PTI backers clashed violently with police in Islamabad and other cities.

Ali Bukhari, a lawyer for Khan, told AFP by phone that the court had approved eight days of physical remand of Khan demanded by the country’s top graft agency.

Afzal Marwat, another of Khan’s lawyers, earlier said Khan was in “good spirits” but had complained of being hit on the head and leg by paramilitary forces who arrested him.

The former cricketing superstar, who remains wildly popular, has previously said the dozens of cases brought against him are part of an effort by the struggling government and military establishment to prevent him from returning to power.

His arrest has brought thousands of his supporters to the streets in several cities.

At least six people have died in protest-related incidents, police and hospitals reported, including one person who died from smoke inhalation after a building was set ablaze in Lahore.

- Confrontation with military -

The arrest and subsequent violence triggered swift reaction from Western powers urging peaceful democracy. On Wednesday the United Nations called on authorities to “respect due process” and rule of law in proceedings against Khan.

UN Secretary-General Antonio Guterres, in noting the protests, “calls for all parties to refrain from violence” and “he stresses the need to respect the right to peaceful assembly,” deputy spokesman Farhan Haq said.

Khan’s arrest came hours after the military rebuked him for alleging that a senior officer had been involved in a plot to kill him.

Pakistan politicians have frequently been arrested and jailed since the country’s founding in 1947, but few have so directly challenged a military that has staged at least three coups and ruled for more than three decades.

Criticism of the military establishment is rare in Pakistan, where army chiefs hold significant influence over domestic politics and foreign policy.

“The senior army leadership is uninterested in repairing the rift between itself and Khan,” said Michael Kugelman, director of the South Asia Institute at the Wilson Center.

“So with this arrest it’s likely sending a message that the gloves are very much off.”

Khan’s close allies expressed concern he could end up tortured while in custody.

“None of us has had any access” to Khan, his former special assistant and PTI member Zulfikar Bukhari told Sky News. “We’re extremely worried that he will be tortured.”

- Internet cut, exams cancelled -

The interior ministry had ordered mobile internet services cut and restricted access to social media sites Twitter, Facebook and YouTube, the country’s communications agency said.

Authorities have ordered schools closed nationwide –- with year-end exams cancelled for students.

Hundreds of police officers have been injured across Pakistan, while in the populous province of Punjab nearly 1,000 people have been arrested.

Some protesters took out their wrath on the military, torching the residence of the corps commander in Lahore and pelting the army’s general headquarters in Rawalpindi with stones.

On Wednesday, the military’s media wing warned of a “strong reaction” against those who attack military and state facilities.

Law Minister Azam Nazeer Tarar told reporters there was “no political vendetta” surrounding Khan’s arrest.

The case that led to his detention was brought by the National Accountability Bureau, Pakistan’s top anti-corruption body, which said he had ignored repeated summons to appear in court.

Pakistan is deeply mired in an economic and political crisis, with Khan agitating for early elections while the government is weighed down by security and economic turbulence.

He has been increasingly outspoken against the establishment, relying on near-fanatical support from the huge crowds that accompany his public appearances to protect him from arrest.