(Reuters) - Former Pakistani Prime Minister Imran Khan said on Friday he would resume his protest march to Islamabad after recovering from an assassination attempt, as his supporters staged nationwide protests that blocked major roads.

Khan was shot in the leg on Thursday as he waved to crowds from a container mounted on a truck from where he was leading a protest march on the capital to press for early elections and calling for the resignation of Prime Minister Shehbaz Sharif.

Sharif led a coalition of parties that ousted Khan from office through a parliamentary vote in April.

"I will give a call to march on Islamabad once I get better," Khan, a former international cricket star-turned-politician, said in a live address on Friday from a hospital in Lahore where he has been receiving medical treatment.

He said two shooters had tried to assassinate him, in a country with a history of politically motivated violence. He said one person was killed and 11 others were injured in Thursday's attack in Wazirabad, about 170 km (106 miles) southeast of Islamabad.

Punjab Health Minister Yasmeen Rashid, a doctor and member of Khan's Pakistan Tehreek-e-Insaf (PTI) party, told Reuters two bullets hit Khan, wounding him in the shin and thigh.

Khan accused three people of devising the plan to assassinate him, naming Sharif, Interior Minister Rana Sanaullah and intelligence official Major-General Faisal Nasser. He did not provide evidence for his claim.

The media wing of Pakistan's military called the allegations "baseless and irresponsible."

"The government of Pakistan has been requested to investigate the matter and initiate legal action against those responsible for defamation and false accusations against the institution and its officials without any evidence whatsoever," the military's Inter Services Public Relations (ISPR) said in a statement.

Sanaullah also rejected the allegations and said the coalition government had demanded an independent investigation. Sharif also condemned the shooting and ordered an investigation.

The military’s media office did not respond to a request for comment on the allegation. It previously condemned the shooting.

Khan's address came after his supporters came out on the streets of major cities on Friday, blocking major roads and clashing in some places with security forces.

Some supporters gathered at the place where Khan was wounded and urged the former premier to resume his march on Islamabad.

"It cannot stop. People are very angry, it will become more intense," Ansar Bashir, 40, a supporter who witnessed the shooting, told Reuters as he gripped a PTI party flag.

In Lahore, the capital of Punjab state in the east, large groups of protesters burnt tyres and blocked roads. Some threw stones at the gate of the Punjab provincial governor's office, destroying security cameras and barriers, witnesses said.

Khan's backers also blocked roads in the northwestern city of Peshawar, while local television channels showed police using tear gas to disperse demonstrators in Islamabad and the southern city of Karachi.

Tahirul Qamar, a medical worker at Wazirabad market, said Khan should halt further protests to avoid more unrest. "He should stop, more lives will be lost," he said.

The interior minister told reporters he was concerned that a video statement, widely carried by local media, in which a man presented as the alleged shooter said he was motivated by religious reasons to attack Khan, could inspire others.

Reuters was unable to confirm authenticity of the video. Punjab police said they had made an arrest, but it was not clear if this was the same person shown in the video footage.

The minister urged the PTI to review Khan's security arrangements.