Munich police said Saturday that the shooter in adeadlyshopping mall rampage was an 18-year-old German-Iranian man whose motive was "completely unclear".

"The perpetrator was an 18-year-old German-Iranian from Munich," police chief Hubertus Andrae told reporters after the massacre Friday that left 10 people dead including the gunman.

"The motive or explanation for this crime is completely unclear."

Andrae said the shooter -- who opened fire at a busy shoppingcentrenear the southern German city's Olympic stadium before turning the gun on himself -- had dual citizenship and "no criminal record".

His body was found about onekilometre(0.6 mile) from the mall.

Twenty-one people were injured in the rampage, 16 of whom were still being treated in hospital. Three were seriously hurt, Andrae said.