The New York Times reported Saturday the top-secret document provides rare insight into eavesdropping by the U.S. security agency. The newspaper said lawyers in the United States with overseas clients have expressed concern such government snooping.
The February 2013 document shows the government of Indonesia had hired the law firm to assist it with trade talks, the Time said. The document states the Australian Signals Directorate conducting surveillance of the talks, including communications between Indonesian officials and the unnamed U.S. law firm, and offered to share the information with the NSA, the newspaper said.
While the law firm wasn't identified in the document, the Times said Mayer Brown, a Chicago firm with a global practice, was advising the Indonesian government on trade issues at the time.
The Times said the NSA declined to answer questions related to the document.
Duane Layton, a Mayer Brown lawyer involved in the trade talks, told the Times he did not have any evidence Australian or U.S. intelligence agencies had been spying on him or his firm.
"I always wonder if someone is listening, because you would have to be an idiot not to wonder in this day and age," he said in an interview. "But I've never really thought I was being spied on."