A gunman opened fire at a campaign truck carrying Pakistan’s former Prime Minister Imran Khan on Thursday, wounding him slightly and also some of his supporters, a senior leader from his party and police said.

Party official Asad Umar said Khan was wounded in the leg and was not seriously hurt. The identity of the gunman, who was arrested at the scene, was not immediately known. No group has claimed responsibility for the shooting.

According to police, the attack happened in the Wazirabad district in the eastern Punjab province where Khan was traveling in a large convoy of trucks and cars heading towards the capital, Islamabad, as part of his campaign aimed at forcing the government to hold early elections.

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 container 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 keg,” Umar told reporters. According to the Interior Ministry, the government has ordered a robe into the incident.

An unspecified number of supporters from his Tehreek-e-Insaf party who were part of the march were also wounded, according to the announcement from the party.

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

Since his ouster in a no-confidence vote in Parliament in April, Khan has alleged that his ouster was a conspiracy engineered by his successor, Prime Minister Shahbaz Sharif, and the United States — claims that both the new premier and Washington have denied.

Sharif’s government has also said that there would be no early vote and that the next elections will be held according to schedule, 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.”

It was also not immediately known if Khan's convoy would proceed on to Islamabad. Earlier, Fawad Chaudhry, a senior leader in Khan’s party, said they plan to enter Islamabad on Friday.