ISLAMABAD — A gunman in eastern Pakistan opened fire Thursday at a campaign truck carrying former Prime Minister Imran Khan, slightly wounding him in the leg and killing one of his supporters, his party and police said. Nine other people also were hurt.

The gunman was immediately arrested at the scene, and police later released a video of him in custody, allegedly confessing to the shooting and saying he acted alone. It was not clear under what conditions he made his statement.

“Only Imran Khan was my target,” said the suspect, identified as Faisal Butt by Information Minister Maryam Aurangzeb.

The attack raised new concerns about growing political instability in Pakistan since Khan’s ouster in a no-confidence vote in Parliament in April.

Since then, he has mobilized mass rallies across the nuclear-armed nation of 225 million, whipping up crowds with claims that he was a victim of a conspiracy by his successor, Prime Minister Shahbaz Sharif, and the United States. Both the new premier and Washington have denied the allegations.

Pakistan has a decades-long history of political assassinations, including that of Benazir Bhutto, the first democratically elected female leader of a Muslim country, in 2007.

Khan was later seen with a bandage on his right leg, just above the foot, according to reports and a blurry image. He was moved to another vehicle from his truck, from where announcements were being made that he was safe.

“He is being taken to a hospital in Lahore, but he is not seriously wounded. A bullet hit him in the leg,” Asad Umar, an official from Khan’s Tehreek-e-Insaf party, told reporters. The Interior Ministry said the government has ordered an investigation of the incident.

The attack happened in the Wazirabad district in the eastern Punjab province where the former cricket star turned Islamist politician was traveling in a large convoy of trucks and cars heading toward the capital of Islamabad. The convoy is part of his campaign aimed at forcing the government to hold early elections.

District police officer Ghazanfar Ali said one person was killed and nine others were wounded in the attack.

Among the wounded was Faisal Javed, a lawmaker from Tehreek-e-Insaf. In a video statement, with bloodstained clothes, He said the attack would not stop Khan’s protest march to Islamabad.

Interior Minister Rana Sanaullah Khan condemned the attack.

Fawad Chaudhry, a senior leader from Khan’s party, told the supporters surrounding Khan’s truck that the attack was an attempt to kill the former premier.

Khan has been at loggerheads with Pakistan’s powerful military and has refused to halt his plans to march on the capital. The military has said that although Khan had a democratic right to hold a rally in Islamabad, no one would be allowed to destabilize the country. Authorities in Islamabad have already deployed additional security around the city to deter any clashes or violence.

The attack came less than a week after Khan began his march from Lahore, the capital of Punjab province, with thousands of supporters.

Earlier, Chaudhry had said they plan to enter Islamabad on Friday.

Sharif’s government has said that there would be no early election and that the next balloting will be held as scheduled in 2023.

Khan’s latest challenge to the government comes after Pakistan’s elections commission disqualified him from holding public office for five years for allegedly selling state gifts unlawfully and concealing assets as premier.

Khan, who has challenged the disqualification in a pending court case, has said he would sue Chief Election Commissioner Sikandara Raja, who was behind the decision, for calling him a “dishonest person.”

The attack comes as the impoverished country is grappling with the aftermath of unprecedented floods that struck this Islamic nation over the summer, killing 1,735 people and displacing 33 million.

Khan’s supporters rallied in different parts of the country hours after the shooting.