WASHINGTON - The FBI and National Security Agency monitored the emails of prominent Muslim-American activists, academics and a political candidate, according to a report co-authored by journalist Glenn Greenwald.
The report appearing in the online news site The Intercept said the surveillance was authorised by a secret intelligence court under procedures intended to locate spies and terrorist suspects.
The report, citing documents in an NSA spreadsheet leaked by former contractor Edward Snowden, showed the emails of the individuals, but not their names.
The Intercept said it identified at least five persons, all American citizens, based on their email addresses.
They were Faisal Gill, a longtime Republican Party operative and one-time candidate for public office; Asim Ghafoor, an attorney who has represented clients in terrorism-related cases; Hooshang Amirahmadi, an Iranian-American professor at Rutgers University; Agha Saeed, a civil liberties activist and former professor at California State University; and Nihad Awad, the executive director of the Council on American-Islamic Relations.
According to the report by Greenwald and Murtaza Hussain, the spreadsheet shows 7,485 email addresses listed as monitored between 2002 and 2008.
Many of the emails appeared to belong to foreigners suspected of being linked to Al-Qaeda, including Anwar al-Awlaki, the Yemeni-American cleric killed in a 2011 drone strike.
But the journalists' investigation also found a number of US citizens monitored in this manner, which requires an order from the secret intelligence court based on evidence linking them to espionage or terrorist activities.
US officials, responding to the report, said communications are only monitored with a "legitimate foreign intelligence or counterintelligence purpose."
"It is entirely false that US intelligence agencies conduct electronic surveillance of political, religious or activist figures solely because they disagree with public policies or criticise the government, or for exercising constitutional rights," said a joint statement from the Justice Department and office of the Director of National Intelligence.
"Unlike some other nations, the United States does not monitor anyone's communications in order to suppress criticism or to put people at a disadvantage based on their ethnicity, race, gender, sexual orientation or religion."
The statement added that a court order for any surveillance of this kind requires "probable cause, based on specific facts," which indicate that the person "is an agent of a foreign power, a terrorist, a spy, or someone who takes orders from a foreign power."
"No US person can be the subject of surveillance based solely on First Amendment activities, such as staging public rallies, organising campaigns, writing critical essays, or expressing personal beliefs," the statement added.