NEW YORK, April 5 (Reuters) – AT&T Latin America Corp. has signed a three-year commitment to buy fiber optic products and services from Canadian telecommunications giant Nortel Networks Corp. that will help it strengthen its operations in the region. AT&T Latin America is majority owned by US long-distance telephone and cable television giant AT&T Corp. and operates in Argentina, Brazil, Chile, Colombia and Peru. The agreement is part of $300 million in commitments that AT&T Latin America obtained last week from Nortel, Lucent Technologies Inc. and Cisco Systems Inc., an AT&T spokeswoman said. In exchange for the commitments, AT&T Latin America committed to make equipment purchases from the three vendors in proportion to their respective financing commitments.