Seven international peacekeepers were killed and 17 wounded when they came under heavy fire from a large group of unknown assailants in Sudan's strife-torn Darfur region on Saturday, the peacekeeping force UNAMID said.
The incident took place in an area where peacekeeping is the responsibility of Tanzanian forces, and was the force's worst death toll from a single incident since it was deployed five years ago.
The "extended firefight" happened near Khor Abeche in South Darfur, the African Union/United Nations-led force said in a statement, without confirming nationalities. Two of the 17 wounded soldiers and police officers were female.
Years of international peace efforts have failed to end conflict in Sudan's western region of Darfur, where mainly African tribes took up arms in 2003 against the Arab-led government in Khartoum, which they accuse of discriminating against them.
Violence is down from its peak in 2004-05, but has picked up again this year as government forces, rebels and Arab tribes, which were armed by the government early in the conflict, are now fighting among themselves over resources and land.
Around 300,000 people have been forced to leave their homes in Darfur this year due to fighting, according to the United Nations.
The International Criminal Court has issued arrest warrants for Sudanese President Omar Hassan al-Bashir and some aides on charges of masterminding war crimes in Darfur. They deny the charges and refuse to recognise the court.
Events in Darfur are hard to verify as Sudan severely restricts travel by journalists, aid workers and diplomats.