BERLIN (AP) — Police in Germany's capital say nine people have been slightly injured when a smoke bomb went off at an event by the Kurdish community.

Berlin police said Monday that nine participants had to be treated for breathing difficulties at the meeting Sunday night which was about Iraq's semi-autonomous Kurdish region decision to hold a referendum on independence next month.

The Turkish government is strictly opposed to such a vote and has warned that a referendum could lead to civil war. Turkey is also involved in a long-simmering conflict with Kurds for more independence in its own southeastern region.

Police said it wasn't clear who was behind the incident in Berlin which was attended by 400 people.