Ethiopia on Saturday slammed the United States for a report that criticised its human rights record, claiming that it demonstrated 'serious intellectual deficiencies'. The US State Department released its annual Human Rights Report on Thursday, which cited complaints of illegal detention, torture and killings, as well as violations of press and religious freedom in Ethiopia. 'The authors actually claim to make 'every effort' to verify all the information in the document. If so, they cannot have tried very hard,' the Ethiopian foreign affairs ministry said in a statement. 'The report frequently repeats erroneous claims from previous years even when the government has provided detailed evidence to the contrary.' The US report also criticised Addis Ababa's handling of its opposition's political campaigns ahead of May elections. Opposition groups have accused Prime Minister Meles Zenawi's ruling party of repeated harassment in order to prolong its stay in power. 'The constitution provides citizens the right to change their government peacefully and to freely join a political organization of their choice,' the report said. 'However, in practice these rights were restricted through bureaucratic obstacles and government and ruling party intimidation and arrest.' Ethiopia, Washington's main Horn of Africa ally, dismissed the claims. 'This report demonstrates serious intellectual deficiencies and flaws, and most seriously, a fundamental and structural difference over how and where democracy can be encouraged in a country like Ethiopia,' it said. Ethiopia's elections will take place on May 23, the first since 2005 when disputed results sparked violence that claimed some 200 lives. 