(Adds U.S. intelligence officials downplaying any link to Islamic State)
By Joern Poltz and Jens Hack
MUNICH, July 22 (Reuters) - An 18-year-old German-Iranian gunman who apparently acted alone opened fire in a busy shopping mall in Munich on Friday evening, killing at least nine people in the third attack against civilians in Western Europe in eight days.
The pistol-wielding attacker, identified by Munich Police Chief Hubertus Andrae as a dual national, was later found dead of a suspected self-inflicted gunshot wound to his head.
Police, citing eyewitness accounts, had initially said they were looking for up to three suspects in the shooting attack at the Munich Olympia Shopping Centre that sent shoppers fleeing in panic and shut traffic across the city.
But authorities told a news conference early on Saturday the shooter was believed to have staged the attack alone, opening fire in a fast food restaurant before moving on to the mall.
Sixteen people, including several children, were injured in the attack and three were in critical condition, Andrae said.
There was no known motive for the shooting in Germany's third largest city, which went into lockdown with transport halted and highways sealed off immediately after the attack.
It was the third major act of violence against civilians in Western Europe in eight days. Previous attacks in France and Germany were claimed by the Islamic State militant group.
"The motives for this abhorrent act have not yet been completely clarified - we still have contradictory clues," German Foreign Minister Frank-Walter Steinmeier said in a statement.
There was no immediate claim of responsibility but supporters of Islamic State celebrated on social media.
"The Islamic state is expanding in Europe," read one tweet.
U.S. intelligence officials, speaking on condition of anonymity, said initial reports from their German counterparts indicated no apparent link between the shooter and Islamic State or other militant groups.
The gunman, whose body was found on a side street near the mall, was not identified by name but Andrae said he was not previously known to police.
The mall is next to the Munich Olympic stadium, where the Palestinian militant group Black September took 11 Israeli athletes hostage and eventually killed them during the 1972 Olympic Games.
Friday's attack took place a week after a 17-year-old asylum-seeker assaulted passengers on a German train with an axe. Bavarian police shot the teenager dead after he wounded four people from Hong Kong on the train and injured a local resident while fleeing.
The police chief said there were no immediate similarities between Friday's attack and the incident on the train near the southern German city of Wuerzburg. (Reporting by Michelle Martin, Joseph Nasr, Tina Bellon, Andrea Shalal, Christina Amann, Karin Strohecker, Editing and writing by Angus MacSwan, Hugh Lawson and Tom Brown)
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