Authorities have named former US Army Reserve soldier Micah Johnson, a 25-year-old African-American, as the lone gunman in Thursday night's sniper attack in Dallas, which came at the end of a march by hundreds of demonstrations decrying the fatal shootings by police of black men earlier in the week. Under President Barack Obama the US has been a key part of Nato. No one is sure what will happen under President Donald Trump, the signals are unclear. Credit:Getty Images Officials said Johnson had embraced militant black nationalism and expressed anger over shootings by police as well as a desire to "kill white people, especially white officers". Dallas remained on edge on Saturday. The police headquarters and surrounding blocks were cordoned off and SWAT teams were deployed after police said they received an anonymous threat against officers across the city. The police said they searched a headquarters parking garage and three floors of the building for a "suspicious person" but no suspect was found. Thursday's rally in Dallas followed the fatal police shootings of Philando Castile, 32, near St Paul, Minnesota, on Wednesday, and Alton Sterling, 37, in Baton Rouge, Louisiana, on Tuesday.

Mr Obama, who is cutting short his European trip on Sunday to visit Dallas, said that "Americans of all races and all backgrounds are rightly outraged by the inexcusable attacks on police, whether it's in Dallas or any place else." Barack Obama in Madrid, Spain, from Poland, on Saturday, on what is expected to be his last presidential visit to Europe. Credit:AP He added they also are rightly saddened and angered about the deaths of Sterling and Castile, and about "the larger, persistent problem of African-Americans and Latinos being treated differently in our criminal justice system." The first black US president whose term in office ends next January, said he hopes he has been able to get all Americans to understand the nation's difficult legacy of race. Devin Cousin of Florence, Mississippi raises his fist as he and about 200 mainly young marchers protest on Friday. Credit:AP

He said Americans cannot let the actions of a few define all. "The demented individual who carried out those attacks in Dallas - he's no more representative of African-Americans than the shooter in Charleston was representative of white Americans, or the shooter in Orlando or San Bernardino were representative of Muslim-Americans," Mr Obama added, referring to a string of mass shootings in the past year. A mother tries to calm her daughter as Dallas police respond to the police shootings on Thursday. Credit:Dallas Morning News/AP Seven other police officers and two civilians also were wounded in Dallas. Johnson was killed by a bomb-carrying robot deployed against him in a parking garage where he had holed up and refused to surrender during hours of negotiations with police, authorities said on Friday. Gun control

Mr Obama, who has been blocked by the Republican-led US Congress in his bid for new gun-control measures, expressed new frustration over lax firearms laws in the United States, saying it is unique among advanced countries in the scale of violence it experiences. "With respect to the issue of guns, I am going to keep on talking about the fact that we cannot eliminate all racial tension in our country overnight. We are not going to be able to identify ahead of time and eliminate every madman or troubled individual who might want to do harm against innocent people. But we can make it harder for them to do so," he said. Illustrating the divide among Americans over gun rights, Republican Texas Attorney General Ken Paxton told Reuters that men like the Dallas gunman "are not going to be confined by a gun law that we pass." Paxton, whose state has among the most permissive gun policies in America, added, "Our goal here in Texas is to protect law-abiding citizens. And since we cannot have a police force that guards every person, we want people to be able to protect themselves." Protests continue

While Thursday's attack stunned Dallas into mourning, it did not stop Black Lives Matter demonstrations around the country against killings by police. In Baton Rouge, there were scuffles between riot police and demonstrators. In Minneapolis, hundreds of protesters marched along city streets and shut down some intersections, with many wearing red, according to organisers, to "symbolise the blood spilled" in the shooting of Castile and others by police. Demonstrators in New York chanted "no racist police, no justice, no peace." Early on Saturday, up to 30 protesters were arrested near police headquarters in Baton Rouge, where the FBI has warned of safety concerns for law enforcement and the general public. Reuters Loading