Stephen Gaghan invaded Oman.

He didn't do it intentionally, of course -- unless he's really an undercover CIA agent posing as a filmmaker. But during the course of making his political thriller "Syriana" in the United Arab Emirates, Gaghan, his crew and an armed camel train did veer into that country's Southeastern neighbor and ended up squaring off with the Omanian army as he, like the characters in his movie, discovered how easily it can be to lose yourself in the invisible borders of the Persian Gulf.

In late 2004, Gaghan's movie filmed in locales ranging from Baltimore and Washington to Geneva and Casablanca, working in five languages over 74 days. Scenes that involved the movie's unnamed oil-rich kingdom, the story line with the impressionable Pakistani teen and the movie's climax were among those shot in and around Dubai, one of the seven city-states that make up the UAE.

Few films have been shot in the UAE, let alone a Western one, and getting permission involved the politics of persuasion and negotiations with the country's royal family. And even when their request was granted, and Gaghan and his crew had arrived in the country, it was taken away.

"They heard that the script was anti-Saudi," says Gaghan, explaining that Saudi Arabia has a multibillion-dollar investor in the country, and the head of the royal family, Sheik Mohammed bin Rashid Al Maktoum, could have found himself in potential choppy political waters by allowing the film.

Luckily, a general in the country's armed forces and the deep connections of Robert Baer, the CIA officer whose book, "See No Evil," the movie is based on, turned things around. "We had support in the intelligence sectors," Gaghan says.

Being in Dubai caused some culture clash, particularly since the production was there during the holy days of Ramadan. Arabs fast all day during that period, and at one point Gaghan and his some of his Western crew hid below dashboards to munch on snacks in order not to offend.

While other movies have shot in Californian deserts or deserts in Africa to double for the Gulf, Gaghan says it is impossible to duplicate elsewhere the unique light of that part of the world.

"We think of the desert as dry heat, like Death Valley dry. But the Persian Gulf has 100% humidity. It's like a wall that hits you," he says. "The air is filled with pink dust (from ongoing industrialization), and in that combination, the light refracts a certain way. What you see in the film is basically unretouched negative. The light actually looks like that. We had to get that feeling of what it is really like."

As for the incursion into Oman: For a scene that ultimately was cut from the movie, Gaghan wanted a camel train traveling along pink sand dunes against the backdrop of mountains. He kept going further and further into the desert to shoot "all these guys who looked like Berber smugglers; they had machine guns and pistols and they were on these huge camels."

That's when the army vehicles arrived, demanding to know what was going on.

The filmmakers explained they had permission from the sheik, that they had permits. "Where do you think you are?" the officers said, scoffing at the paperwork. When the dust settled, Gaghan was told he had wandered into Omani territory and the production was ordered to turn back.

Gaghan says the whole Dubai experience was eye-opening.

"It was exciting to bring a big Western movie there in these times," he says.