The 21-year-old worked on the Academy Award-nominated documentary The White Helmets, and the Associated Press (AP) reported he was blocked by immigration authorities from entering the country on Saturday (25Feb17).

According to documents seen by the AP, Homeland Security officials decided at the last minute to block Khateeb from traveling to Los Angeles.

He was due to arrive on Saturday on a flight from Istanbul, but his plans were scrapped after U.S. officials allegedly found “derogatory information” about the cinematographer.

Khateeb was previously granted a visa to attend The Oscars on Sunday (26Feb17), where The White Helmets is nominated for Best Documentary Short. He was detained by Turkish authorities and told he needed a waiver from the U.S. to enter the country, which he was not able to obtain.

The White Helmets, a 40-minute documentary, focuses on the rescue workers who risk their lives to save Syrians affected by civil war.

Trump's travel ban, which restricted travel into the U.S. by citizens from seven Muslim-majority countries, caused uproar when it was introduced last month (Jan17). At the time, Khateeb said he still planned to travel to the country for the Oscars.

“I plan to travel to L.A. for the Oscars, where the film is nominated for an award,” he said. “If we win this award, it will show people across Syria that people around the world support them. It will give courage to every volunteer who wakes up every morning to run towards bombs.”

"If I cannot enter the U.S., I will not give up: We know that we have many friends in the U.S., that there are people that share our humanitarian values. I look forward to meeting them all one day," he added.

Trump's executive order restricting the travel of citizens from the seven countries, as well as halting all refugee immigration programs, has since been suspended.