The US Secretary of State Rex Tillerson has warned that China and Russia are assuming alarming roles in Latin America and urged regional powers to work with the United States instead.<br/><br/>Latin America does not need new imperial powers that seek only to benefit their own people, Tillerson said in a speech at his alma mater, the University of Texas in Austin, before embarking on his first multination trip to South America. <br/><br/>He also derided Russia for selling weaponry to unfriendly, authoritarian governments in the region. <br/><br/>After the speech, Tillerson left for Mexico City to meet with Mexican President Enrique Pena Nieto and other senior officials.<br/><br/>