* Sri Lanka under international pressure to address abuses
* U.N. rights chief to release initial report in September
* Pillay visit draws demonstrations for and against
By Shihar Aneez and Ranga Sirilal
COLOMBO, Aug 30 (Reuters) - Sri Lankan President Mahinda Rajapaksa told the United Nations human rights chief on Friday that his people believe the U.N. is a biased organisation, and a ...