ISLAMABAD (AP) — Pakistan’s Imran Khan and his lawyer met Monday at a high-security prison where the former prime minister is being held following his sentencing, to plan how to challenge the graft case that landed him behind bars more than a year after he was ousted from power.

A national cricket hero and top opposition leader, Khan was sentenced over the weekend to three years for concealing assets after selling state gifts while in power and taken to Attock, a high-security prison in eastern Punjab province.

The stunning sentence could bar him from politics as Pakistani law prohibits anyone with a criminal conviction from holding or running for public office, and may cost him the chairmanship of the party he founded, Pakistan Tehreek-e-Insaf, or PTI.

Khan’s lawyer, Naeem Haider Panjutha, told reporters after their meeting Monday that Khan was in good spirits and maintaining “a high morale” despite the harsh conditions at the prison, which is known for holding convicted militants and the most hard-core criminals during trial proceedings.

Khan is being held in a “small room where there is no air conditioner and where there are flies in daytime and insects at night,” the lawyer said, insisting that Khan should get better facilities in prison.

“He says he can spend the whole of his life in such conditions but will not bow down,” Punjutha said.

Their meeting took place in the presence of jail officials, the lawyer said and added that Khan had given him the green light to petition the Islamabad High Court against the conviction on Tuesday. He said Khan’s legal team had already petitioned a court seeking better prison facilities for him.

The lawyer said Khan had asked to see his wife, Bushra Bibi, and his personal physician — requests that the legal team will also submit to prison authorities, Panjutha said. He added that Khan was praying and reciting the Quran, Islam’s holy book, and given the same food as other prisoners.

According to the lawyer, Khan also praised his supporters and asked them to continue peaceful protests against his imprisonment.

Shah Mehmood Qureshi, who is leading Khan’s party in his absence, also denounced the prison conditions, saying Khan was being denied his basic rights.

Khan’s prison term started on Saturday, but it was not immediately clear if he will spend the three-year sentence in Attock. Authorities have further tightened security around the prison, which already has armed guards in watchtowers, by erecting barriers and blocking roads to keep people away. They have also instructed locals not to allow media onto their roofs to stop photographs and videos from leaking.

Khan was previously arrested in May on corruption charges — an arrest that triggered a wave of violent protests that swept the country. Days later, Pakistan’s Supreme Court ordered his release, saying his arrest was illegal.

Since his sentencing Saturday, Khan’s renewed call for mass protests have failed to gain traction among his supporters. On Sunday, hundreds gathered on the outskirts of Muzaffarabad, the capital of the Pakistan-administered Kashmir region, to condemn the arrest.

Khan has claimed that his ouster from power was a conspiracy by Washington, the government of his successor, Prime Minister Shehbaz Sharif, and the Pakistani military — accusations that all three deny.

Panjutha also recounted to reporters that Khan told him how security forces on Saturday broke the door of his bedroom to arrest him and dragged him out of his home in Lahore, the capital of Punjab, and forced him into a vehicle.