The gunman who killed nine people in Munich was a student obsessed with mass shootings and had no known links to the Islamic State group, German police say.

Police who searched his room found newspaper clippings on attacks including an article entitled "Why do students kill?", police told reporters.

The killer, who was born in Munich, 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.

Police also said there was an "obvious link between the gunman and Norway's mass killer Anders Behring Breivik, who murdered 77 people in July 2011.

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

Three of the victims were from Kosovo. The father of one of them, 21-year-old Dijamant Zabergja, was photographed holding a photo of his son near the mall on Saturday. The other two were young women.

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

Munich, capital of the southern German state of Bavaria, was rocked by the attack.

Flags are to be flown at half-mast across Germany in mourning and Chancellor Angela Merkel has delayed a holiday in the Alps to chair a meeting of the national security council .

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

Critically ill

Munich police chief Hubertus Andrae warned the number of injured could increase if people who had fled the scene came forward.

Ten of the injured 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 Zequiri, 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.

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

The name of the gunman, who was 18 and of ethnic Iranian origin, was not given.

His body was found about 1km (half a mile) from the mall.

The attack came 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.