Pakistan’s opposition leader was blocked from boarding a flight out of the country on Saturday, the Associated Press reported.

Shahbaz Sharif, the head of the lower house of parliament and the Pakistan Muslim League, who has been charged with corruption, was prevented from boarding a Qatar Airways flight to London. His spokeswoman said immigration officials at the Lahore airport notified Sharif that his name was on a “black list.”

Sharif — a cancer survivor — had reportedly been seeking treatment outside Pakistan. On Friday, the Lahore High Court ruled he could go abroad for treatment through early July.

Prime Minister Imran Khan, of the Pakistan Movement for Justice, had criticized the decision, and said it would seek to stop Sharif from leaving.

Sharif’s older brother, Nawaz Sharif, Pakistan’s former premier, lives in London. He was convicted of corruption and released in 2019 on bail to seek medical treatment, but never returned.