ISLAMABAD - Media freedom advocacy groups and journalists in Pakistan have demanded authorities immediately reveal the fate and whereabouts of a popular television anchor arrested nearly two weeks ago.

Imran Riaz Khan was taken into custody on May 11 from the airport at Sialkot, an industrial city in the Punjab province, as he tried to leave the country over fears of his arrest, according to family members and attorneys. But police have said they no longer have the reporter in custody.

Daniel Bastard of the France-based global watchdog Reporters Without Borders, or RSF, said in a statement Tuesday it had received information from 'confidential diplomatic sources' that the missing journalist was tortured and 'may even have died in detention.'

The 47-year-old reporter was among thousands of people detained earlier this month during a nationwide crackdown on supporters of the opposition Pakistan Tehreek-e-Insaf, or PTI, party and its leader, popular former Prime Minister Imran Khan.

The missing journalist, unrelated to the popular PTI chief, was known for hosting pro-Khan talk shows on the mainstream BOL television channel and for his more than 4 million YouTube subscribers.

On Monday, the journalist was scheduled to be produced before a court in Lahore, in the provincial capital, in response to a complaint filed by his father last week. But the police chief told the judge there was no trace of the television anchor.

'We have asked police across Pakistan. No one has Imran Riaz,' Usman Anwar, the Punjab police chief, said during the court hearing. 'However, agencies had asked for a police van. Why they had asked for a police van, [the court] can summon the agencies and ask,' Anwar said, referring to the country's military intelligence agencies.

The judge ruled in response to the police chief's statement the 'failure of the police to ascertain the fate and whereabouts of the missing citizen of the country is clear from the information.' The court will reconvene on Thursday.

Bastard, the head of RSF's Asia-Pacific desk, urged Prime Minister Shehbaz Sharif to immediately release the missing reporter, saying the Pakistani authorities would be held 'directly responsible' for any harm that may have come to him.

Amnesty International said in a separate statement the case of the missing journalist 'constitutes an enforced disappearance under international human rights law.' It demanded Imran Riaz Khan be immediately released.

The watchdog lamented that enforced disappearance had been a 'worrying trend' in Pakistan for many years and is used to punish 'dissenting voices.'

The missing journalist was in the past widely seen as a close ally of the powerful military but began criticizing the institution in support of the ousted Khan.

Several journalists known for airing programs in favor of the former prime minister have fled Pakistan.

Khan was removed from power by a parliamentary vote of no confidence in April 2022, a move he rejected as illegal and plotted by the powerful military. According to opinion polls, the cricket star-turned-prime minister remains the most popular politician in Pakistan.

The deposed leader has held massive anti-government rallies since his dismissal, where he openly named army generals for toppling his government and calling Sharif the 'puppet' of the military.

Paramilitary forces violently arrested Khan on May 9 on corruption charges from outside a court in the capital of Islamabad. He was released on bail two days later, but his supporters staged protests over his arrest for several days, clashing with riot police and assaulting government property, including military buildings.

The PTI chief and his aides have since condemned the attacks on military installations. Khan says more than 10,000 supporters, including senior leaders, have been arrested without police investigations, alleging operatives of intelligence agencies were behind the attacks on military facilities.

Sharif and the military chief, General Asim Munir, have said those involved in violence against army property will be tried in military courts, prompting criticism and demands by human rights groups to strike down the controversial decision.