BERLIN - German police say 15 officers were injured by an explosive device as protests against the government's planned budget cuts turned violent.

Police in Berlin on Sunday said that some 450 militant leftists joined a protest march of several thousand people on Saturday and attacked police by throwing stones and bottles. At one point, an explosive device was hurled toward police.

Thirteen officers were slightly injured by splinters from the device, but two officers were severely wounded and remain hospitalized. Prosecutors opened an investigation for manslaughter.

Police did not provide more details on the explosive device.

Konrad Freiberg, the chief of Germany's main police union, said in a statement: "That was attempted murder."