WASHINGTON (Reuters) - The U.S. National Security Agency collected 534 million records of phone calls and text messages of Americans last year, more than triple gathered in 2016, a U.S. intelligence agency report released on Friday said.

The sharp increase from 151 million occurred during the second full year of a new surveillance system established at the spy agency after U.S. lawmakers passed a law in 2015 that sought to limit its ability to collect such records in bulk.