Pakistan's former prime minister Imran Khan on Saturday alleged that "three criminals", who were behind the failed assassination attempt on him early this month, are waiting to target him again.

Addressing a mega rally of his Pakistan Tehreek-e-Insaf party here in this garrison city, which houses the headquarters of the powerful army, Khan said he had a close encounter with death and had seen bullets flying overhead during the attack on him.

In his first in-person address to the party workers after the failed assassination bid on his life, Khan alleged that "three criminals" who he claimed were behind the attack on him are waiting to take a shot at him again.

The 70-year-old leader has repeatedly alleged that Prime Minister Shehbaz Sharif, Interior Minister Rana Sanaullah and ISI Counter Intelligence Wing head Maj-Gen Faisal Naseer were behind the attack on him.

Khan called on his supporters to free themselves from the fear of death if they wanted to live freely.

"Fear makes an entire nation into slaves," he said, referring to the battle of Karbala in present day Iraq where the Prophet's grandson Imam Hussain was killed along with his family members for raising his voice against the tyrant ruler of his time.

Khan, who was accompanied by a team of doctors as he arrived in a helicopter in the garrison city of Rawalpindi on Saturday, said everyone had advised him when he was setting out from Lahore not to do so due to his injured leg as well as the threats to his life.

He said he went ahead because he had seen death from close range.

"If you want to live life, shun the fear of death," he said.

Khan said the nation stands at a "defining point" and "crossroads" with two paths before it - one path was one of blessings and greatness while the other path was of humiliation and destruction.

He is leading the long march, demanding early general elections, months after he was ousted from power.

Earlier, Khan was advised to wear a bulletproof jacket, should not exit the vehicle on the way to the rally's venue and keep his movement secret.

The former cricketer-turned-politician said on Friday that despite being injured he is determined to head to Rawalpindi for the sake of the nation.

Khan was ousted from power in April after losing a no-confidence vote in his leadership, which he alleged was part of a US-led conspiracy targeting him because of his independent foreign policy decisions on Russia, China, and Afghanistan. The US has denied the allegations.

He is the only Pakistani prime minister to be ousted in a no-confidence vote in Parliament. The term of the current National Assembly will end in August 2023.