President Obama says the U.S. is reviewing whether to put North Korea back on its list of state sponsors of terrorism as Washington decides how to respond to what he calls an 'act of cybervandalism' against Sony. North Korea has reacted angrily to Obama's comments blaming it for the hacking of Sony, warning of strikes against the White House and Pentagon. For its part, Sony Pictures, which said it canceled the theatrical release of 'The Interview' after distributors refused to show it, pledged to find a way to get the film out. The U.S. is asking China for help as it considers how to respond to the hack. China wields considerable leverage over North Korea, but Obama has also accused China of carrying out cyberthefts. North Korea has denied hacking the studio, and proposed a joint investigation with the U.S.