Complex sentence: There were some problems reported in the north, where ex-Koevoet elements searched villages for SWAPO returnees; however, the UN reported that this was kept under constant surveillance by UNTAG's police monitors.
Split into simpler sentences: There were some problems reported in the north when ex-Koevoet elements searched villages for SWAPO returnees. The UN reported that this was kept under constant surveillance by UNTAG's police monitors.