Manuel Tello was appointed Ambassador to the United Nations in 1957 after serving in the Mexican Foreign Service. From 1971 to 1982, he served as representative to the Third United Nations Conference on the Law of the Sea in Caracas, Venezuela; Geneva, Switzerland; and New York City, United States. In 1988, he was appointed Eminent Ambassador of Mexico before becoming the Permanent Representative of Mexico to the United Nations in 1993. From 1994 to 1995, Ambassador Tello served as the Minister of Foreign Affairs and then returned to his post as Permanent Representative to the United Nations in 1995.
Conducted on 6 August 1997, together with Ambassador Gustavo Albin of the Mexican Consulate to the United Nations, this interview centred on the role Mexico played in the peace processes in Central America as well as their participation as a Friend of the Secretary-General for the El Salvador, Nicaragua and Guatemala Peace Processes.