Plane terror alert: Obama vows to 'root out extremism'

US President Barack Obama has said that two packages originating in Yemen and destined for the United States do "appear to contain explosive material".

Speaking to the American people, the US president vowed that his country would do all it could to "root out extremism in all its forms".

The suspect packages were intercepted in Dubai and Britain.

Cargo planes were also searched at Newark in New Jersey, and Philadelphia.