A group opposed to Chinese rule in the mainly Muslim region of Xinjiang has claimed responsibility for a series of recent bombings around the country, saying they were part of a campaign against next month's Beijing Olympics.

Chinese officials have repeatedly raised the possibility of a terrorist attack and used it to justify a security crackdown. But the claims - brought to media attention by IntelCenter, the US terrorism monitoring company - are certain to heighten security concerns around the Olympics, which open on August 8.