Pakistan's former prime minister Imran Khan on Thursday in his Eid greetings to fellow countrymen said this year's Eid festival was the "most painful" one for him.

Taking to Twitter to wish people, the Pakistan Tehreek-e-Insaf (PTI) chairman said about 10,000 of his supporters in jail were being treated as criminals after his supporters attacked military installations and government buildings following Khan's arrest in a corruption case on May 9.

"For me, this is the most painful and painful Eid. Nearly 10,000 of our activists and supporters have been jailed while being treated like criminals for exercising their constitutional right to peaceful protest," the 70-year-old cricketer-turned-politician tweeted.

Khan's PTI party found itself in hot water after violent protests erupted across the cash-strapped country following their leader's arrest on May 9 in the Al-Qadir corruption case by the National Accountability Bureau (NAB) from the premises of Islamabad High Court.

Khan's supporters allegedly torched more than 20 military installations as well as civilian buildings in the aftermath of the arrest of their leader. Khan was later released on bail.

"Our brave leaders, including women leaders like Dr Yasmin Rashid and Alia Hamza etc., continue to refuse to be jailed and disaffiliated from Tehreek-e-Insaaf," he said.

"Sixteen of our workers were shot and martyred, while the other 8 are suspected to have been killed, but this cannot be confirmed because their loved ones and friends are underground for fear of the police. 50 others were also shot," Khan said, adding that no independent investigation was conducted to ascertain facts about the "Black Day" violence.

"On the contrary, through one-sided propaganda against Tehreek-e-Insaf at the official level, everyone who has even the slightest relation to Tehreek-e-Insaaf, under the sole aim of crushing Tehreek-e-Insaaf in any way before the elections. But the mountains of oppression and terror were broken," he said.

He was however confident that his PTI and the (Pakistani) nation will emerge from this dark period much stronger than before.

"Imran Riaz Khan was abducted and it has been more than 40 days that no one knows about his safety and whereabouts. In this way, our 5 reliable journalists had to leave the country and take shelter elsewhere. On this Eid, we are also making them a part of our memories," he said, adding that the media was being muzzled and the critics of the "fascist government were on the target of the State wrath".

Khan, who is demanding an early general election, is hoping that his party will return to power. The term of the current National Assembly will expire in August and a fresh election should be held within 60 days.