Gunman kills four in Oklahoma medical centre, police say

A man armed with a rifle and a handgun killed four people inside a medical building in Tulsa, Oklahoma on Wednesday before fatally shooting himself, and officers' quick response to the incident helped ensure more people were not harmed, police said.

Police arrived at the St Francis Hospital three minutes after receiving a call about the shooting and followed the sound of gunfire up to the Natalie Building's second floor...