After eight years as head of satellite news channel Al-Jazeera, Wadah Khanfar has resigned amidst a Wikileaks controversy alleging he agreed to alter the content of the channel’s website at the request of the U.S.

According to a U.S. embassy cable released by Wikileaks on Aug. 30, Khanfar agreed to “tone down” objectionable content on the station’s website and promised to “remove it over the subsequent two or three days.”

Website Middle East Online alleges the leaked document was used by Qatari officials to exert pressure on Palestinian-born Khanfar, especially after he waded into controversy with fellow Palestinian activist Azmi Bishara, also based in Qatar.

Khanfar’s replacement is believed to be Sheikh Ahmed bin Jassim Al Thani, a member of Qatar’s ruling dynasty that backs the Doha-based satcaster.

In a farewell note to staffers on Tuesday, Khanfar said he had discussed his desire to step down with the board, which had accepted his decision.

Khanfar’s note said, “Renewal and change is always good. I have served Al-Jazeera with pride as a correspondent, bureau chief, managing director and director-general.”

Under his tenure, the satcaster grew into one of the most powerful news channels in the region, with spinoffs in a variety of languages including English.

Al-Jazeera was a force for change during the recent Arab Spring uprisings. But Khanfar has been criticized by some Arab commentators who say his sympathy for the Muslim Brotherhood shows in often favorable coverage of Islamist movements.

(Bobbie Whiteman in Hollywood contributed to this report.)