The gunman who killed five police officers and wounded seven more, was planning an even larger attack, the Dallas police chief says.

Micah Johnson, 25, had become enraged by the recent killings of unarmed black men by police across the US, and police chief David Brown said he was “convinced” Johnson had wider plans to kill more white police officers in revenge.

Police found bomb-making materials at Johnson’s home, and said he appeared to have practised detonating explosives.

Johnson was killed in a remote detonation by police after exchanging fire with police and claiming that he had explosives.

Johnson shot at police officers on Thursday during a peaceful ‘Black lives matter’ protest in Dallas, one of a number of protests across the US following the deaths of Philando Castile in St Paul, Minnesota, and Alton Sterling in Baton Rouge, Louisiana, last week.