In this June 20, 2009, file photo, tourists walk through the Potala Palace, the former home of the Dalai Lama before he fled Tibet after a failed Tibetan uprising against Chinese rule in 1959. (Greg Baker/AP)

Free Tibet and the International Campaign for Tibet, two groups that campaign for an independent Tibet, reported a clash between Chinese security forces and Tibetan protesters Monday.

An unidentified “Free Tibet” protester demonstrates in London in November 2005. (Jane Mingay/AP)

Retuers tried to independently verify the information, but was unable to when a security bureau officer hung up on the reporter.

This time of year is particularly sensitive in Tibet, with Tibetans often refusing to celebrate Monday’s Lunar New Year, a major holiday in China. Tibetans celebrate the new year in mid-February. For four years — since an uprising in 2008 — China has closed Tibet to foreign travelers during mid-February. Travel agents told the Associated Press last week that the Chinese government would close the region this year.

There have been other reports of outbreaks of violence in the region this year. The advocacy groups reported a woman shot in January when protests started after a Buddhist monk set himself on fire. At least 16 Tibetans are believed to have set themselves on fire in the past year, the Associated Press reports.