Top American leaders on Friday called for calm after a series of racial motivated shootings, including the deadliest killing of five police officials in Dallas, stunned the US.
Five officers were killed and another 12 injured in a shooting in Dallas on Thursday night during a peaceful protest that was organised in response of the tragic deaths of Alton Sterling in Louisiana and Philando Castile in Minnesota.
The US Attorney General Loretta Lynch said an FBI investigation will be launched into the Dallas killing.
The US Department of Justice has opened a civil rights investigation in Louisiana and is providing assistance to local authorities in Minnesota who are leading the investigation there, she said.
"After the events of this week, Americans across the county are feeling a sense of helplessness, of uncertainty and of fear. These feelings are understandable and they are justified. But the answer must not be violence. The answer is never violence," Lynch said.
"Rather, the answer must be action: calm, peaceful, collaborative and determined action. We must continue working to build trust between communities and law enforcement. We must continue working to guarantee every person in this country equal justice under the," the Attorney General said.
US President Barack Obama said America is horrified over these killings.
"We stand united with the people and the police department in Dallas," he said at Warsaw where he is meeting with NATO and European Union leaders.
Obama has ordered that the national flag fly at half-staff in honour of the victims of the Dallas attack.
Taking the podium on the floor of the US House of Representatives, Speaker Paul Ryan said he is stunned by the events of Thursday night in Dallas.
"We are all outraged. An attack on the people who protect us is an attack on all of us," he said.
"There will be a temptation to let our anger harden our divisions. Let's not let that happen. There's going to be a temptation to let our anger send us further into our corners. Let's not let that happen. That script is just easy to write -- it’s too predictable. Let's defy those predictions," he said.
"A few perpetrators of evil do not represent us. They do not control us. The blame lies with the people who committed these vicious acts, and no one else. And as the president rightfully said, justice will be done," Ryan said.
"I'm horrified by the murder of five law enforcement officials in Dallas and the wounding of many other officers and innocent civilians," said Senator John McCain.
IMAGE: A Dallas police sergeant wears a mourning band on his badge during a prayer vigil in a park following the multiple police shooting in Dallas, Texas, US. Photograph: Carlo Allegri/Reuters