Two police officers killed in US

Two police officers have killed in what authorities have called 'ambush-style' attacks in the US state of Iowa.

Both were shot dead as they sat in patrol cars a couple of miles apart in Des Moines.

Early this morning the first officer was discovered in a suburb of Des Moines – while the second was found with gun shot wounds a short time later a couple of miles away.

Officers are now patrolling in pairs.