US Secretary of State Condoleezza Rice has challenged Kazakhstan to be a leader of economic and democratic reform in Central Asia. Speaking in the Kazakh capital Astana, she called for the country\'s presidential elections set for December to be free and fair. Human rights groups have accused President Nursultan Nazarbayev of clamping down on opposition groups. They also expressed disappointment at Ms Rice\'s speech. The American Secretary of State deliberately avoided criticising President Nazarbayev. She did, however, call on the region to tackle corruption, which she described as a tax on the poor. But in a question and answer session following her speech, an opposition leader asked Ms Rice why she had not been more critical of what he called the country\'s authoritarian regime. He said the press was closed and dissenters had been jailed. In her reply, Ms Rice said it was extremely important that opposition voices could mobilise without fear of intimidation. However, speaking to reporters later, opposition figures expressed disappointment that the US secretary of state had not been more direct. They accused the US of putting security and energy interests ahead of pressing for democratic reform. Later, at a joint news conference with President Nazarbayev, Ms Rice denied that she had softened her message because of US oil interests in the country. (BBC)