Bomb making material found in Dallas suspect's home

A black US Army reservist who served in the Afghan war and said he wanted to "kill white people" took part in an attack in which five police officers were shot dead at a peaceful protest decrying police shootings of black men, officials said on Friday.

Investigators identified the dead suspect as 25-year-old Micah Xavier Johnson of Mesquite, Texas, a military veteran who'd served in Afghanistan.

Police said they searched his home Friday afternoon and found bomb-making materials, ballistic vests, rifles, ammunition and a personal journal of combat tactics.

Investigators are analysing information in the journal, a police statement said.

Seven other police officers and two civilians were wounded in the ambush in downtown Dallas on Thursday night.

Police killed the gunman, identified by a US government source as Micah Xavier Johnson, with a bomb-carrying robot after cornering him in a parking lot, ending the hours-long standoff.

The US Army said that Johnson had served as a private first class in the Army Reserve and was deployed to Afghanistan from November 2013 to July 2014.

Peaceful demonstrations thorough the US had been organised in response to the fatal shootings of two black men by police this week in Louisiana and Minnesota.

On Tuesday morning, 37-year-old Alton Sterling was shot and killed by a white officer in Baton Rouge, Louisiana.

His killing was captured on video by a bystander.

The following day, Philando Castile, a 32-year-old school cafeteria manager, was killed in Falcon Heights, Minn., as his girlfriend was broadcasting his final moments in real time over the social media platform Facebook.

President Barack Obama called Dallas Police Chief David Brown and US Attorney General Loretta Lynch on Friday, while traveling in Poland for a NATO summit, to get an update on the investigation into the Texas shootings, White House spokesman Josh Earnest said.

"The president also offered his condolences on behalf of the country to Chief Brown for the officers who were killed in last night's shootings," Earnest said.

Social Media Reaction:

Hashtags #PrayFor Dallas, #BlackLivesMatter, #Castile and #Sterling trended globally.