Washington (Web Desk): The US Department of Homeland Security barred a young Syrian cinematographer who worked on the documentary The White Helmets and has been nominated for an Academy Award.

Khaled Khatib, 21, was flying to Los Angeles on Saturday but was stopped from boarding the plane, despite having a valid US visa. Khatib was detained in Istanbul, Turkey after the US Department of Homeland Security informed Turkish officials they had unspecified “derogatory information” about him. Derogatory information is a broad category that can include anything from terror connections to passport irregularities.

The Associated Press, which had access to internal US documents about Khatib, said he would not get the passport waiver that he needed to enter the US. Khatib filmed most of the 40-minute Netflix documentary The White Helmets, which follows rescue workers for the Syrian Civil Defence White Helmets who have saved tens of thousands of lives during the nation’s bloody civil war.

The group, founded in 2012, was nominated for a Nobel Peace Prize in 2016. Khatib, who started filming the workers when he was just 16, is also a volunteer with the group. Some 120 White Helmets volunteers have been killed in recent years.