Police officer: school shooting 'worst thing ever seen'

US President Barack Obama has called for "meaningful action" in the wake of a shooting at a Connecticut school that left 27 dead, including 20 children.

Newtown Police Lieutenant George Sinko described his reaction on receiving the emergency call from Sandy Hook Elementary School.

He said the scene at the school was "horrific - something that no-one should have to see".

"This is the definitely the worst thing I've ever had to see in my career."