Video has emerged which purportedly shows the moment snipers opened fire at a protest march in downdown Dallas, Texas.
A male voice can be heard in the video, which was uploaded to Twitter, saying: "Somebody's really armed to the teeth. This is not one person".
The father of Dallas shooting victim police officer Patrick Zamarripa said he was 'angry' about his son's death, but called for more unity.
James Johnson, whose son Micah shot and killed five white police officers, said: "I love my son with all my heart but I hate what he did."
A mother caught up in the attacks praised police as heroes with "no regard" for their own safety as they worked to protect her family.