JOHN YANG:

In the day's other news: Syria denied U.S. claims that it's using a crematorium to conceal mass executions of thousands of prisoners. The Foreign Ministry called it categorically false and said it's a new Hollywood plot to justify American intervention.

The State Department accused Syria of incinerating the corpses of executed prisoners to destroy evidence that could be used in war crimes prosecutions.

North Korea has become the prime suspect in the global cyber-attack. A growing number of cyber-security experts now say the lines in the ransomware code are identical to lines in the code used by previous hackers linked to the North.

And, they say, there are other clues.