Khan, 70, who was ousted as prime minister in April, was six days into a protest procession, standing and waving to thousands of cheering supporters from the roof of a container truck when shots rang out.

Several others in his convoy were wounded and Information Minister Marriyum Aurangzeb said a suspect had been arrested after the attack in Wazirabad, nearly 200km from Islamabad.

In purported footage of the shooting, being run by multiple channels, a man with a handgun is grabbed from behind by one of the people at the gathering.

He then tries to flee.

TV channels showed a man they said was a suspected shooter, who looked to be in his twenties or thirties.

He said he wanted to kill Khan and had acted alone.

“He (Khan) was misleading the people, and I couldn’t bear it,” the suspect said in the video.

The information minister confirmed the footage was recorded by police.

Khan had been whipping up large crowds on his way to the capital Islamabad in a campaign to topple the government of Prime Minister Shehbaz Sharif.

One member of Khan’s party said there were reports one person had been killed in the attack.

“It was a clear assassination attempt. Khan was hit but he’s stable. There was a lot of bleeding,” Fawad Chaudhry, a spokesman for Khan’s Pakistan Tehreek-e-Insaf (PTI) party, told Reuters.

“If the shooter had not been stopped by people there, the entire PTI leadership would have been wiped out.”

He wrote on Twitter: “It was a well-planned assassination attempt on Imran Khan, the assassin planned to kill Imran Khan and leadership of PTI, it was not 9mm it was burst from automatic weapon, no two opinions about that it was narrow escape.”

Local media showed pictures of Khan waving to the crowd after being removed from his vehicle following the shooting.

He was taken to hospital in Lahore as protesters poured out onto streets in some parts of the country and PTI leaders demanded justice.

PTI colleague Faisal Javed, who was also wounded and had blood stains on his clothes, told Geo TV from the hospital: “Several of our colleagues are wounded. We heard that one of them is dead.”

Prime Minister Sharif condemned the shooting and ordered an immediate investigation.

Since being ousted through a parliamentary vote, Khan has held rallies across Pakistan, stirring opposition against a government that is struggling to bring the economy out of the crisis that his administration left it in.

Khan had planned to lead the motorised caravan slowly northwards up the Grand Trunk Road to Islamabad, drawing more support along the way before entering the capital.

“I want that all of you participate. This is not for politics or personal gain, or to topple the government … this is to bring genuine freedom to the country,” Khan said in a video message on the eve of the march.