Police presence across Germany and around mosques was stepped up on Friday as hundreds flocked to attend prayer in the central city of Hanau where nine people were killed on Wednesday evening.
Interior Minister Horst Seehofer said that surveillance is reinforced at "sensitive sites" including mosques with a higher police presence at transport hubs and borders.
"The threat posed by far-right extremism, anti-Semitism and racism is very high in Germany," Seehofer told reporters.
It comes after the German Central Council of Muslims demanded a higher security presence at places of worship.
Nine people were shot dead in two hookah lounges in Hanau on Wednesday evening. Authorities have identified the suspect as 43-year old Tobias R.
Officials also confirmed that they had received a letter from the suspect back in November in which he demanded they put an end to the surveillance he believed himself to be under. The letter didn't ring alarm bells with prosecutors, officials said.
Thousands of people across Germany gathered in some 50 cities across Germany on Thursday evening to pay tribute to the victims.
In Berlin, mourners convened in front of the Brandenburg Gate to form a human chain.
'Poison' in German society
Authorities believe the suspect had a far-right motive for the killing. They revealed that he had posted a rant calling for the "complete extermination" of "many races or cultures in our midst".
The man was found dead at his home. Another body was found at the address, said to be the man's 72-year-old mother. The man is believed to have killed her before ending his own life.
Chancellor Angela Merkel said the shooting exposed the "poison" of racism in German society and pledged to stand up against people who seek to divide the country.
"There is much to indicate that the perpetrator acted out of far-right extremist, racist motives,``" she said. "Out of hatred for people with other origins, other faiths or a different appearance."
In a statement released on Thursday, the Central Council of Muslims "strongly" condemned the attack. It added that the perpetrator's "racist ideology is by no means an isolated case", citing recent deadly attacks in Christchurch, Halle and Oslo.
"Those who still do not clearly name or even downplay anti-Muslim racism are complicit in the bloody violence against minorities and promote fascism in our country," Council Chairman Aiman A. Mazyek said.
"I call on Muslims in Germany to be more vigilant and also take their own protective measures for themselves, their families and places of worship and institutions," he added.
The bar attacks happened minutes apart, late on Wednesday night in two districts of Hanau, a city near Frankfurt in central Germany. The bars have been identified as "Midnight" and the "Arena" cafe. Hookah lounges -- or shisha bars -- are places where people gather to smoke flavoured tobacco from Middle Eastern water pipes.
Turkish authorities have reported that five Turkish nationals were among those killed. President Erdogan has called on Germany to get to the bottom of what happened.
The authorities have confirmed that they are investigating a racist motive for these attacks, and are examining possible far-right material linked to the suspected gunman. Germany has been on alert for far-right extremism.
Federal prosecutors -- which investigate serious crimes including terrorism -- have taken over the case and the authorities say they suspect a far-right motive.
Police said a video was taken down from social media sites on Thursday morning. Reports have suggested the suspect left a "letter of confession", which is being investigated.
The interior minister for the state of Hesse, Peter Beuth, said a website believed to be the suspect's was being evaluated.
"Initial analysis of the webpage of the suspect indicates a xenophobic motivation," he said, adding that federal prosecutors were treating the attacks as domestic terrorism.
"This is an attack on our free and peaceful society," Beuth said.
The area where the shootings took place has a large Kurdish community. The Turkish embassy in Berlin reported that five Turkish nationals were among those killed. Earlier, a lawmaker in Hesse's state parliament said he believed the victims came from Turkish and North African backgrounds.
German media reports say investigators found ammunition in the suspect's car, adding that he had a hunting licence. Police are said to have carried out check-ups on his background and to have found nothing untoward, Euronews correspondent Jessica Saltz reported from Hanau.
- Watch Euronews TV coverage of the atrocities in the video player above.
In the aftermath of the shootings, police officers swarmed central Hanau, cordoning off the area of one of the shootings as a helicopter hovered overhead. A car covered in thermal foil also could be seen, with shattered glass next to it. Forensic experts in white overalls collected evidence.
Initially, police said that eight people were killed and around five wounded -- another fatality was confirmed later. They said a dark vehicle was spotted leaving the location of the first attack and another shooting was reported later at a second scene, about two-and-a-half kilometres away.
Officers sealed off and searched the apartment where the suspect was found dead in Hanau's Kesselstadt district, near the scene of one of the shootings, after following up witness statements on a getaway car.
`"This was a terrible evening that will certainly occupy us for a long, long time and we will remember with sadness," Hanau Mayor Claus Kaminsky told the Bild newspaper. Lawmaker Katja Leikert, a member of Chancellor Angela Merkel's centre-right party who represents Hanau in the German parliament, tweeted that it was ``"a real horror scenario for us all".
Hanau is about 20 kilometres east of Frankfurt. It has about 100,000 inhabitants and is in Hesse state.
Police from neighbouring Bavaria were deployed to help their local colleagues, DPA news agency reported.