SBA Communications Corp. said Wednesday that it reached a deal to expand its presence in Brazil with the purchase of about 2,000 wireless sites from Oi SA, one of Brazil’s largest telecommunications service providers, for about $645 million.

Jeffrey Stoops, the communications tower operator’s president and CEO, said that the sites are concentrated in the most populous areas of Brazil and are attractive to tenants. The deal also establishes SBA as one of the largest independent tower operators in Brazil, he said.