Pakistan's former prime minister Imran Khan on Tuesday told the Lahore High Court (LHC) that a third assassination attempt has been hatched against him and sought to quash all political cases against him, saying regular court appearances will endanger his life.

Khan has filed a petition in the LHC requesting it to quash all 121 cases registered against him in different cities of the country on various charges like treason, blasphemy, committing and inciting violence and terrorism.

According to the petition, the cases have been instituted on political grounds.

Khan, 71, appeared before the LHC amid high security. During the case hearing he requested the court to allow him to speak.

The court acceded to his request.

Khan, the Pakistan Tehreek-e-Insaf party chairman told the court that his life is in danger.

"Regular appearances in courts will expose my life to danger. I survived two assassination attempts on my life -- one in Wazirabad, Punjab, and the other at Islamabad Judicial Complex Islamabad where the ISI had taken charge of the building," a court official told PTI quoting Khan as saying.

"They (a reference to powers that be) want to kill me and a third assassination attempt is in the offing," Khan told the court.

He said in 70 years of his life, there was not a single case against him and all these cases were filed after he was ousted as prime minister in April last year.

The official said the five-member bench of LHC headed by Justice Ali Baqar Najafi directed Khan to join police investigations into these cases on May 5.

"The court did not entertain the request of Khan to appear before the police investigation through a video link. However, the court will resume its hearing on May 8," the official said.

Earlier, Khan claimed that he had identified a total of 'six persons' in the country in a video who wanted to kill him.

"Among the six, three are those whom I had named in the FIR after an assassination attempt on my life in Punjab in November last year," Khan said on Thursday.

After the November 3 gun attack on his rally in the Wazirabad area (some 150kms from Lahore) in which he suffered bullets injuries to his leg, Khan blamed Prime Minister Shehbaz Sharif, Interior Minister Rana Sanaullah and ISI's top officer Major General Faisal Naseer for hatching a plot to assassinate him.

"Interior minister (Sanaullah) says my life is under threat from foreign agencies. Let me make it clear to the entire country that the only threat to my life is from the 3 people I named after the Wazirabad assassination attempt. Same 3, 3 more I have identified in a video statement, tried to eliminate me on March 18 in ICT Judicial Complex," Khan said in a series of tweets.

"If any attempt is made now on my life, these same people will be responsible. Just as they tried to pin the blame for the Wazirabad attack on a religious extremist - a mere smokescreen - they are now trying to create another deception of foreign agencies," he said.