German Chancellor Angela Merkel said her country is in "deep and profound mourning" after nine people were killed by a lone gunman on a rampage in Munich.
The 18-year-old German-Iranian attacker, named in reports as Ali Sonboly, went on a solo shooting spree at the Olympia shopping centre and a McDonald's restaurant in the Bavarian capital on Friday.
Born and raised in the German city, he murdered nine people and injured 27 others - 10 of whom are in a critical condition, including a 13-year-old boy.
At a press conference on Saturday Mrs Merkel said the events are "difficult to bear for everyone" and pledged to "find out the background" of what happened.
She added: "What lies behind the people of Munich is a night of horror - we are still shocked by the pictures and reports of the witnesses.
"Nine people who were going shopping on the Friday evening, or wanted to eat something, they are now dead - it seems according to the investigations, hit and killed by the bullets of one single perpetrator."
The Chancellor said the operation between the agencies and security forces on Friday night was "seamless" and thanked them for their "phenomenal" effort.
She added: "We are in deep and profound mourning for those who will never return to their families. The families, siblings, friends to whom everything will be void and empty today.
"I would like to tell them, in the name of many, many people in Germany, we share in your grief, we think of you and we are suffering with you.
"Our thoughts also go out to the numerous injured people - may they recover quickly and completely - they will receive all the support they need.
"Such an evening and such a night are difficult to bear for every one of us. They are even more difficult to bear because we have had so many different and difficult reports of horrors in the past few days."
Officials said the killer used a 9mm pistol and had 300 rounds of ammunition in his rucksack when he went on what they called a "classic shooting rampage".
Police said the weapon was a Glock 17 handgun which had had its serial number illegally filed off, and there were indications the gunman had been in psychiatric care and treated for depression.
They confirmed his room in the flat he was living in had been searched, and that documents of "frenzied attacks" had been discovered, but no evidence he had links to Islamic State.
According to reports the killer had an "obvious" link to Norwegian mass-murderer Anders Behring Breivik - who, five years to the day of the Munich attack, slaughtered 77 people.
Police investigator Robert Heimberger told a police press conference in Munich that it appeared the gunman had hacked a Facebook account and lured people to the shopping centre with an offer of free food.
The posting, sent from a young woman's account, urged people to go to the centre at 4pm, saying: "I'll give you something if you want, but not too expensive."
Mr Heimberger said they are investigating as "it appears it was prepared by the suspect and then sent out".
Officials said the attacker was not known to them and had no criminal record. He had been in psychiatric care and was treated for depression. He later killed himself.
Three of the victims are believed to be from Kosovo, three from Turkey and one from Greece - seven of the dead are understood to be teenagers.