Tensions are running high as the U.S. prepares to decide whether or not it will follow through with military action against Syria, but Syrian President Bashar al-Assad is still denying that he ever used chemical weapons against his own people.

In an interview with CBS's Charlie Rose, Assad said there is "not a single shred of evidence" that the Syrian government used chemical weapons, despite what the White House and other officials have said.

On top of its email and phone call surveillance, the National Security Agency also has access to data on all major smartphones like the iPhone, Blackberry and Android devices, according to a new report from German news weekly Der Spiegel.