BERLIN-A powerful German drama about a soldier fighting the Taliban in Afghanistan and his unlikely friendship with a local interpreter premiered Tuesday at the Berlin film festival.

"Inbetween Worlds" by Feo Aladag was filmed over six weeks in northern Afghanistan. The director said she put her actors through a kind of "boot camp" and worked with a European-Afghan crew to achieve authenticity. Ronald Zehrfeld, who starred in the 2012 hit "Barbara" about an escape attempt from the former communist East Germany, plays Jesper, a soldier whose brother was killed in Afghanistan.

His unit is fighting to protect a village from the Taliban but, nearly as frequently, clashing with the locals over customs and laws. Tarik (Mohsin Ahmady) is an interpreter who has the high-risk task of bridging the cultural and linguistic distance between the foreign troops and frightened villagers. With Tarik's help, Jesper seeks to gain the trust of the locals and the allied Arbaki militia, but finds himself at odds with his own commanders who keep their distance from the Afghans.

The gulf between religions, and between rich and poor, plays out in their daily interactions but Jesper and Tarik find common ground in their desire to help. When it becomes clear that Tarik's sister, a university student, is under threat from the Taliban, Jesper must choose between his duties as a soldier and his own moral compass. "German Bundeswehr soldiers, when they swear their oath, oblige themselves to ultimately follow their own conscience and not the chain of command - this is an important point with regard to German history," Aladag told reporters.

The Vienna-born Aladag, 42, worked as a journalist before making "When We Leave", a drama about so-called honour killings which won New York's Tribeca Film Festival in 2010. "Inbetween Worlds" is her second feature and one of 20 films in competition for Berlin's Golden Bear top prize, to be awarded on Saturday. The film comes as more than 50,000 combat troops from the US-led NATO force are planning to pull out by the end of this year.

Most of the 3,000 German troops deployed in Afghanistan are based in the northern city of Mazar-i-Sharif. Fifty-four German soldiers have died there. Germany is currently embroiled in a fierce debate over playing a more robust role in international military missions in the world's crisis zones. Zehrfeld said he wanted to shine a light on the moral responsibilities of those back at home in whose name the troops are deployed.

"We citizens gave legitimacy to the parliament and the parliament gave legitimacy to the deployment- and these soldiers come back marked by their experiences," he said. "We want to assume more foreign policy responsibility and we need to look at what that means." Jawed Taiman, the production manager in Afghanistan, said that the threat to locals who work with foreigners was very real.

"Working in media in Afghanistan, you're kind of blacklisted for them (the Taliban)," he said.  "So the danger is there for everybody every day." Aladag said Germany lagged behind countries such as the United States, Britain and New Zealand in expediting visa requests for local helpers in Afghanistan. "The work of interpreters is not only on the level of words but also to convey a sense of where the person is coming from, to make people truly understand each other," she said.