WARSAW/DALLAS, July 9 (Reuters) - President Barack Obama urged Americans on Saturday not to see the country as being riven into opposing groups, seeking to soothe raw emotions after an attack that killed five policemen in Dallas and the high-profile police shootings of two black men in Minnesota and Louisiana.
"First of all, as painful as this week has been, I firmly believe that America is not as divided as some have suggested," Obama said.
"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," he said, speaking at a news conference during a trip to Poland. "That includes protesters. It includes family members who have grave concerns about police conduct, and they have said that this is unacceptable."
Authorities have named former U.S. Army reservist Micah Johnson as the lone gunman in Thursday night's attack in Dallas, which came at the end of a rally to protest against police killings. They said he had embraced militant black nationalism and expressed anger over police shootings and a desire to "kill white people, especially white officers."
"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," Obama said, referring to a string of mass shootings in the past year.
The attack in Dallas also wounded seven other officers and two civilians. Johnson, 25, 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.
Obama, while saying there was a "persistent problem of African-Americans and Latinos being treated differently in our criminal justice system," stressed he did not believe the country was descending into the polarization seen in the sometimes violent civil rights struggles of the 1960s.
He cited almost uniformly peaceful protests against police killings, and police handling the protests with professionalism.
The 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.
Obama reprised a frustration he frequently expresses over lax gun laws in the United States, saying the country is unique among advanced countries in the scale of violence experienced.
Referring to the death of Castile, after a traffic stop, Obama said "we don't know yet what happened, but we do know that there was a gun in the car that apparently was licensed but it caused, in some fashion, those tragic events."
PROTESTS CONTINUE
While Thursday's attack stunned Dallas into mourning, it did not stop demonstrations around the country against police killings.
Thousands of protesters took to the streets in several cities on Friday for a second day. They clogged roadways in New York, Atlanta and Philadelphia, and events in San Francisco and Phoenix also drew large crowds.
More demonstrations were planned for Saturday in Minnesota, Louisiana, New York and Washington, D.C.
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.
The first detentions began when a group of protesters linked arms and sat down in a roadway, blocking traffic. Tensions rose on both sides after an officer pulled a weapon during the demonstration. No shots were fired and Baton Rouge police said they were reviewing the incident.
Police use of force, particularly against African-Americans, has come under intense and sometimes angry scrutiny in the past two years because of a string of high-profile deaths in cities from Ferguson, Missouri, to New York.
Dallas Police Chief David Brown on Friday that said the gunman cited his anger over police killings during his protracted negotiations with police.
Police initially thought that the gunshots that erupted on Thursday evening came from multiple shooters. But by late Friday, investigators had concluded that Johnson, armed with a rifle, was the lone gunman, and did not have links to, or inspiration from, any international militant group. Still, officials said they were looking for evidence of any possible co-conspirators.
A senior national security official said on Saturday that his information from the FBI and Dallas police was that there was still no serious reason to believe there was a second shooter. The official, who spoke on condition of anonymity, added that at this point there was no evidence of a conspiracy.
A search of the gunman's home just outside Dallas found bomb-making materials, ballistic vests, rifles, ammunition and a personal journal of combat tactics, though he had no previous criminal history, police said.
Police said social media entries showed he subscribed to a militant black nationalist ideology, including an anti-white diatribe posted last week on a Facebook page of a group called the Black Panther Party Mississippi.
The death toll in Dallas was the highest for U.S. police in the line of duty from a single event since the Sept. 11, 2001, attacks on New York and Washington. Other police departments across the country, including New York, Chicago and St. Louis, responded to the attack by requiring officers to patrol in pairs rather than alone.
(Additional reporting by Adam DeRose, Jeff Mason and Arshad Mohammed in Washington, Bryn Stole in Baton Rouge, David Bailey in Minneapolis and Mark Hosenball in London; Writing by Frances Kerry; Editing by Leslie Adler and Mary Milliken)