By Adrienne Mong, NBC News Producer

CHENJIABA, Sichuan Province – It all started out friendly enough.

Our team ran into a pair of young volunteer rescue workers in the ghostly mountain village of Chenjiaba.

They were drawn to NBC News cameraman Dmitry Solovyov and his TV camera, offering to carry his tripod, even his backpack, while chatting amiably with researcher Sarah Jiang and me about the work they'd done in the quake-devastated area.

It was the same when we met Gao, who was overseeing a brigade of firemen from Ningxia province who had just arrived. He was fresh-faced and ready for the daunting clean-up challenges that lie ahead.

VIDEO: Chinese media unusually open up after quake

"You media are very hard-working," said the jovial-looking Gao. "Coming to report this story is not easy."

"Oh, we think your job is much tougher," we chorused back. "What you're doing is so admirable."

It wasn't long before our little lovefest came to an end.

Change of tune
As Dmitry filmed the firemen sifting through the debris of a collapsed town market, Gao and his sidekick began to get uneasy and started to ask questions.

"Who do you work for?" demanded Gao's sidekick, who refused to give his name. "Do you have permission to be here?"

Adrienne Mong / NBC News

A flattened building in Chenjiaba

As Sarah tried to mollify him, Gao saw me clipping on a microphone for a stand-up I was preparing to file. Immediately he demanded that we stop filming.

"I don't want you press reporting about my men. I don't want you using them as a background and saying negative things like CNN did with their Tibet reporting," he said.

CNN and a handful of other western media outlets had been accused in China's blogosphere of deliberate bias against the Chinese in its coverage of the Tibet unrest in March. 

Adrienne Mong / NBC News

Firemen from Ningxia Province on the move in Chenjiaba.

We went ahead with our stand-up, but an attempt to film a second one was blocked by a fireman.

"I can't let you film here. You are interfering with our work," said Gao.

"But we have permission to be here, given by your superiors, and you are interfering with our work," I responded.

Gao walked away. We walked away.

The two young rescue volunteers watched this exchange with interest. One of them whispered to me, "Are you German media?"

He was referring to the Berliner Morgenpost, a German newspaper vilified on Chinese websites for publishing a photograph of Nepalese troops beating up Tibetan protesters and running a caption that mistakenly identified the Nepalese as Chinese soldiers.

We sighed. No, we were not German media. He smiled apologetically and hoisted Dmitry's knapsack back on his shoulders and picked up the tripod, offering to continue showing us around Chenjiaba.