Former Pakistan Prime Minister Imran Khan was shot in the shin on Thursday when his anti-government protest convoy came under attack in the east of the country in what his aides said was a clear assassination attempt by his rivals.

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

Several in his convoy were wounded in the attack in Wazirabad, nearly 200 km (120 miles) from the capital. Information Minister Marriyum Aurangzeb said a suspect had been arrested.

"It was a clear assassination attempt. Khan was hit but he's stable. There was a lot of bleeding," Fawad Chaudhry, a spokesperson 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."

Another Khan aide, Asad Umar, said doctors had told him that their leader was out of danger.

In a video statement, Umar said Khan believed that Prime Minister Shehbaz Sharif and intelligence official Major-General Faisal Naseer were behind the attack. Umar did not provide any evidence to back the allegation.

Aurangzeb, who speaks for the government, did not respond to a request for comment on the allegation. Sharif condemned the shooting and ordered an immediate investigation.

The military’s media wing did not immediately respond to a request for comment on the allegation against Naseer.