The gunman who killed nine people in Munich was obsessed with mass shootings and had an obvious link to Norwegian mass murderer Anders Behring Breivik, German police say.

Police who searched the 18-year-old's room say they found written material on attacks.

The gunman, who later killed himself, had a 9mm Glock pistol and 300 bullets.

Police are investigating whether he may have lured his victims through a Facebook invitation to a restaurant.

He is suspected of using a fake account under a girl's name to invite people to the McDonald's restaurant where he launched his attack.

Friday evening's attack at the Olympia shopping mall also left 27 people injured, including children.

Seven of the dead were teenagers. Three victims were from Kosovo, three from Turkey and one from Greece.

Police say the gunman had been in psychiatric care, receiving treatment for depression.

Flags are to be flown at half-mast across Germany in mourning and Chancellor Angela Merkel is chairing a meeting of the national security council .

People could be seen laying flowers and lighting candles outside the mall on Saturday.

'Obvious' link

Munich police chief Hubertus Andrae said there was an "obvious" link between the new attack and Friday's fifth anniversary of Breivik's attacks in Norway, when he murdered 77 people.

A spokesman for the Munich prosecutor, Thomas Steinktaus-Koch, said the killer might have been receiving psychiatric care.

"We are assuming that he may have suffered from depression," he said. "As far as we know he has no criminal record. In 2012 and 2010 he was a victim of an attack - on one occasion he was beaten by three young offenders."

Andrae warned the number of injured could increase if people who had fled the scene came forward. Ten people were critically ill, including a 13-year-old boy, he said.

First reports of the shooting came in just before 18:00 (16:00 GMT) on Friday.

Witnesses say the attacker opened fire on members of the public in Hanauer Street before moving on to the mall.

A grainy video appears to show a man firing a gun outside McDonald's as people flee.

Another video shows the gunman walking around alone on a flat roof before again opening fire. He can be heard shouting at the person filming, saying at one point, "I'm German".

Witness Luan Zeqiri, who was in the shopping centre, told German broadcaster N-TV the attacker had been wearing military-style boots and a backpack.

"I looked in his direction and he shot two people on the stairs," he said.

Zeqiri said he hid in a shop, but when he left, he saw dead and wounded people on the ground.

Police said the gunman was a dual German-Iranian national who was born in Munich. His name has not been released.

His body was found about 1km (half a mile) from the mall. He had no known links to the Islamic State (IS) militant group, police said.

Police have ruled out any connection to the self-styled Islamic State (IS) group.

Fears of a new IS attack had been high just four days after a teenage Afghan asylum seeker stabbed and injured five people on a train in Bavaria before being shot dead by police.

Claiming the attack, IS later released a video showing the 17-year-old brandishing a knife and making threats.