BEIRUT - Rescue workers from Syria's White Helmets group - the subject of an Oscar-nominated documentary-will not attend this weekend's Academy Awards ceremony because of intensified conflict and a rejected passport.

Raed Saleh and Khaled Khatib had been set to attend Sunday's ceremony in Hollywood, where The White Helmets is shortlisted for best short documentary.

"After 3 days at airport, not allowed to travel to#oscars2017 - had US visa - but passport not accepted. Sad, but important work to do here," Khatib tweeted.

US Customs and Border Protection spokesman Michael Friel said "individuals need valid documents to travel to the United States," declining further comment.

Khatib, who shot much of the footage, had obtained a US visa but also cited a heavy workload due to intensified conflict. "I won't travel to OSCAR due to intensity of work, our priority is helping our people," he tweeted. "I'm also working on producing another film about the White Helmets that has to be ready in two weeks," he said by phone.

The two rescuers had feared they could be barred from attending the ceremony because of US President Donald Trump's late January executive order imposing a 90-day entry ban for citizens of seven Muslim majority countries, including Syria. The ban has since been lifted by a US federal court, and on Feb 18, the pair received their visas.

Since the White Helmets group was created in 2013, it has hired more than 3,000 volunteers and claims to have saved more than 78,000 lives. It takes its name from the protective headgear worn by its members.

Agence France-Presse