Thousands of people took part in vigils across Germany on Thursday after a gunman with far-right beliefs killed nine people at a shisha bar and a cafe in the town of Hanau.
Chancellor Angela Merkel condemned the "poison" of racism, as anger mixed with grief over the latest and deadliest attack linked to Germany's extreme right in recent months.
Gunman Tobias Rathjen, 43, was found dead at his home after the rampage along with his 72-year-old mother in what appeared to be a murder-suicide.
The nine people killed at the two bars late on Wednesday evening were aged between 21 and 44 and all had a "migrant background," although some were German citizens, chief federal prosecutor Peter Frank said.
Rathjen first killed three Turkish men dining in a cafe and a Turkish waiter before driving to a second cafe where he killed a 20-year-old Turkish man, a 20-year-old Bosnian and a Polish waitress in the "Arena" hookah bar.
The 35-year-old pregnant mother-of-two called Mercedes died at the scene.
Hundreds of people, many carrying candles or a white rose, gathered in silence in Hanau in the evening to show solidarity with the victims.
Large crowds also gathered in Frankfurt and at Berlin's Brandenburg Gate, some carrying signs that read "Take racism personally" or "Never Again!", in scenes replicated across dozens of German cities.
Mr Frank said that evidence, including video footage and a "manifesto" found on the suspect's website, showed Rathjen had "a very deeply racist attitude".
On Friday Germany's Federal Minister of the Interior Horst Seehofer said security was being heightened at mosques and "sensitive sites" and announced a high police presence at railway stations, airports and borders.
Minister of Justice Christine Lambrecht was due to meet with the chairman of the Central Council of Muslims in Germany, Aiman Mazyek and the spokesman for the Muslim Coordination Council, Zekeriya Altug.
Speaking in Berlin on Thursday, Mrs Merkel said: "Racism is a poison, hatred is a poison and this poison exists in our society and it is already to blame for far too many crimes."
She recalled the murders carried out by the neo-Nazi "NSU" cell between 2000 and 2007, as well as last June's killing of pro-migrant politician Walter Luebcke as examples of the threat posed by the far right.
She also cited October's deadly anti-Semitic attack in Halle, which raised alarm over rising anti-Jewish hatred in Germany.
Wednesday's rampage started at around 10pm at the Midnight shisha bar in central Hanau, some 20 kilometres east of Frankfurt.
The gunman reportedly rang the doorbell and then shot at people in the smoking section.
He fled the scene by car before opening fire at the Arena Bar and Cafe.
After a massive manhunt, the suspect was found dead at his flat, along with his mother. Both were killed by gunshot.
Relatives and friends of the victims gathered at the Arena bar on Thursday tearfully embracing one another.
"I couldn't be any more upset," said Inge Bank, 82, who lives near the bar.
"We have to nip it in the bud if the Nazi party is coming back."
German President Frank-Walter Steinmeier placed a wreath of white flowers outside the Arena bar on Thursday evening before addressing the main Hanau vigil.
Mr Steinmeier condemned the shooter's "brutal act of terror".
But he said he was heartened to see "thousands, maybe even tens of thousands" turning out across the country to honour the victims.
"We stand together, we want to live together and we show that over and over again. That is the strongest way to fight hatred," he said, to the occasional shout of "Nazis Out!" from the crowd.
Elsewhere, Frankfurt's Eintracht football team held a minute's silence ahead of its Europa League match against RB Salzburg.