SACRAMENTO, California, June 24 (Reuters) - American Blake Leeper broke South African Oscar Pistorius's T43 paralympic world record in the 400 metres when he ran 45.25 seconds at the U.S. athletics championships on Friday, officials said. "It is hard to believe. To run 45.25 to break the world record, I am excited for the future," said the 27-year-old Tennessee native who lives in Southern California.

Leeper finished a non-advancing seventh in the semi-final race despite competing as a double amputee.

Pistorius set his record of 45.39 seconds at Daegu, South Korea in August, 2011.

Paralympic gold medallist Pistorius is serving a six-year jail term after being found guilty of murdering his girlfriend in 2013.

(Reporting by Gene Cherry in Sacramento, California; editing by Amlan Chakraborty) ((Gene.Cherry@thomsonreuters.com; +1 646 894 2254;; Reuters Messaging: gene.cherry.thomsonreuters.com@reuters.net))