The African Union (AU) Peace and Security Council has decided that the issue of the "deteriorating security situation" in the western Sudanese region of Darfur be refered to the UN Security Council.
The decision, taken at the end of an emergency meeting on Monday in the Ethiopian capital, Addis Ababa, came after the killing and kidnapping of AU peacekeepers in the region.
Togolese ambassador Esaw Koffi told journalists the AU unreservedly condemned the weekend violence against its personnel.
The AU special representative to Darfur, Baba Gana Kingibe, told reporters in Addis Ababa the 53-nation bloc was "deeply concerned" about the violence, which he said had been increasing since August.
"The international community should be very alarmed by these events because the situation is getting out of hand and we are sliding backwards," he said ahead of the crunch meeting.
"The situation is spiralling. We have a highly aggravated, deteriorating security situation. We have had some very terrible tragedies, but this is one of the lowest points - if not the lowest - that we have had," he added.
Two Nigerian peacekeepers and two contractors were killed on Saturday after rebels opened fire on them, while another soldier died from his injuries on Sunday. Three other troops were wounded in the gun battle.
It was the first time the AU had suffered fatalities in the region, where it has over 6,200 troops monitoring a fragile ceasefire between rebels and government-backed militias.