The conservative Tea Party movement in the United States has won a key Republican Party primary election for the Senate mid-term elections in November.
The Tea Party's Rand Paul has defeated Republican establishment favourite Trey Grayson in Kentucky, according to early results. With 43% of precincts reporting, Mr Paul had 60% of the vote to Mr Grayson's 36%.
The former vice-presidential candidate Sarah Palin, who backed Mr Paul, told the Associated Press that his victory was a "wake-up call for the country".
Mr Paul said: "It's just a tremendous mandate for the Tea Party. It cannot be overstated that people want something new; they don't want the same-old-same-old politicians, and I think they think the system is broken and needs new blood."
Mr Paul - son of one-time presidential candidate Ron Paul - and Mr Grayson, Kentucky's Secretary of State, were vying for their party's nomination for the seat being vacated by retiring senator Jim Bunning.
Voters in several other US states are also deciding on party candidates for November's mid-term elections. The outcome of these primary ballots will be seen as a key indicator of the volatile political mood in America.
In Arkansas and Pennsyvlania, incumbent Democratic senators Blanche Lincoln and Arlen Specter respectively are facing strong challenges from within their party.