Three children were killed and one was wounded Sunday after wandering into a minefield, officials said.
Maj. Tony White, a spokesman for the NATO-led peace force, said a team of NATO explosives experts was immediately sent to assist, but he could give no further details.
The accident happened not far from Sarajevo, but the exact location was not immediately known.
Up to 3 million land mines and unexploded devices are believed to be still scattered across Bosnia.
Scores of people have been killed or wounded in mine-related incidents.