McClatchy's Beijing bureau chief, Tim Johnson, is currently working in Sichuan province and barred from crossing the border into Tibet. He's coordinating work from stringers and colleagues working in Gansu and Qinghai provinces among the ethnic Tibetan population there.

Johnson just blogged what he's seeing there:

We foreign reporters all take precautions. We have to switch vehicles often. Some of us swap out SIM cards in our mobile phones, or just turn them off. That way, authorities cannot triangulate mobile phone signals and figure out our locations.

None of us are doing anything illegal. It's just that it's very easy for officials in the hinterlands to stop us and ask endless questions, creating delays, or simply bar us from entering areas for unspecified security reasons.

Earlier today, I saw probably 100 or more military trucks on a highway heading to Tibet. I have no idea what they were carrying or if it was a routine caravan. It's all part of the riddle of trying to decipher what is happening, and what will happen, in Tibet.

I may get stopped in the next 24 hours. But I'll do my best to wriggle out of it.

Meanwhile, Wired.com has posted a guide to locating live coverage from local sources in Tibet and China online, while China has blocked YouTube and expelled foreign journalists from Tibet.

This morning, the Dalai Lama threatened to resign as Tibet's political-leader-in-exile if the violence escalates.

(Video: Anti-government protest by ethnic Tibetans in Xiahe, China)