Having already failed in multiple attempts to destroy roadblocks erected by Kosovar Serbs in the nation’s north to protest NATO efforts to impose a ban on cross-border trade, NATO’s troops launched another offensive today, lobbing tear gas at local demonstrators.

But whereas past attempts ended with the crowds waiting for NATO to leave then immediately setting up another roadblock, today they clashed with the NATO forces, wounding at least 21 soldiers.

The protesters threw stones at the NATO troops, and also tried to dump gravel on them using the trucks that set up the roadblocks in the first place. The only serious injury on the NATO side was when one of them was hit with a truck.

Several of the Serb protesters suffered injuries related to the use of tear gas, as well as attacks by NATO troops with batons. No figures for injuries on the protesters’ side were released, however.