Bulk data storage allows for the "potential of abuse", President Obama has said, as he announced plans to curb the National Security Agency's authority.
"While few doubt the legitimacy of spying on hostile states, individuals acting on their own is a new threat," Mr Obama said.
"These signals intelligence efforts have prevented multiple attacks and saved innocent lives, not just in the United States but around the globe. But the risk of government overreach has also become more pronounced".
More top news
The Duke of Cambridge is to end his role as an air ambulance pilot and become a full-time Royal, Kensington Palace has announced.
The UN released the before and after images and described the damage, reportedly caused by Islamic State, as 'a new war crime'.
The 16-year-old's body was found on January 16 on a pathway in Dinnington, South Yorkshire.