Four gunmen have killed at least four police officers after shooting 11 and planted bombs after what has been described as a ‘ambush style’ assault.

The coordinated shooters positioned themselves in ‘elevated positions’ to sniper officers during a protest over what many have described as  ‘cold blooded murders’ of two black men by police officers.

Three gunmen have been taken into custody but the last gunman send a strong warning to police from where he is holed up, telling them bombs have been planted all over Dallas, Texas, and warning them ‘the end is coming’.

Officers have already found one suspicious package near to where the gunman is holed up and a bomb squad was called in.

Videos being uploaded on Facebook show one gunman gunning down a police officer who was trying to take on the gunman.

Out of the eleven police officers shot, four police officers have been confirmed dead and three more are said to be in a critical condition.

The shootings happened during a protest demanding justice for the two black men who were killed by police this week.

Police Chief Brown said that it appeared the shooters ‘planned to injure and kill as many officers as they could’.

The suspects ‘have threatened to plant a bomb in the downtown area’, Brown added.

It is not known if the shooters were protesters, however they appear to have been militarily trained.