STORY: Former Pakistan Prime Minister Imran Khan was shot in the shin on Thursday (November 3) in what his aides called a clear assassination attempt.
His anti-government protest convoy came under attack in the east of the country.
Several others in the group were wounded, including party colleague Faisal Javed, who was photographed bleeding.
Pakistan's information minister said a suspect had been arrested.
Local TV channels ran this footage released by Khan's party of the suspected shooter.
"Imran Khan was misleading people. And I could not bear that. That is why I did this. So I killed him -- tried to kill him. I tried my best to kill him. Only Imran Khan. I did not want to kill anyone else."
One party member said there were reports of a fatality.
A spokesperson for Khan's Tehreek-e-Insaf (PTI) party said to Reuters, quote: "If the shooter had not been stopped by people there, the entire PTI leadership would have been wiped out."
Local media showed pictures of 70-year-old Khan waving to the crowd after being evacuated from his vehicle following the shooting.
He was taken to hospital in Lahore after the attack in Wazirabad, nearly 120 miles from the capital Islamabad.
Protesters poured out on to streets in some parts of the country as PTI leaders demanded justice.
Pakistan has a long history of political violence.
Former Prime Minister Benazir Bhutto was assassinated in December 2007 in a gun and bomb attack after holding an election rally near Islamabad.
Before Thursday's attack former cricketer Khan was leading a protest march on Islamabad to demand snap elections.
Since being ousted in April through a parliamentary vote, he has has held rallies across Pakistan
- stirring opposition against a government that is struggling to bring the economy out of the crisis that Khan's administration left it in.