Four Togolese peacekeepers have been shot and wounded in separate attacks in Sudan's Darfur region, the AU-UN mission said on Saturday.
The attacks occurred on Friday, the same day the head of the African Union-United Nations Mission in Darfur (UNAMID), Ibrahim Gambari, expressed concern that rebels were exploiting a deadly stand-off between Sudan and South Sudan.
Eleven Central African troops belonging to a regional border task force were killed on Wednesday on the Darfur side of the boundary by rebels using gunfire and rocket-propelled grenades, officials in Bangui said.
The Togolese police were attacked by unidentified gunmen just before noon on Friday as they were returning to their base in Murnei, West Darfur state, after patrolling in a camp for internally displaced people, UNAMID said.
A rescue team arrived about one hour later and the peacekeepers again moved towards Murnei, but an ambush wounded two more UNAMID members, the mission said in a statement.
"The... team returned fire, but the perpetrators fled," it said, adding the policemen then reached their base and the wounded were taken to a UNAMID hospital.
They are in stable condition, UNAMID said.
"In the climate of ongoing tensions between Sudan and South Sudan, I am deeply concerned that armed movements are seeking to destabilise Darfur," Gambari said in a statement on Friday.
His comments followed three separate rebel attacks in the southern part of the vast Darfur region last Tuesday.
The Central African troops killed on Wednesday belonged to a joint Sudan-Chad-Central Africa border monitoring force, a Central African officer said.
They died when rebels attacked a Sudanese army base that also housed the Central Africans, the officer said.
Border clashes between Sudan and South Sudan escalated last week with waves of air strikes hitting the South, and Juba seizing the north's Heglig oil hub on April 10.
The 10-day occupation appeared to be coming to an end after Sudan on Friday said its soldiers had "liberated" the oilfield by force, and South Sudanese President Salva Kiir announced that "an orderly withdrawal will commence immediately."
Key Darfur rebel groups last year joined a Sudanese Revolutionary Front with insurgents from the states of South Kordofan and Blue Nile on the border with South Sudan.
The rebels pledged to topple the Khartoum regime, which they regard as unrepresentative of the country's political, ethnic and religious diversity.
But they deny fighting alongside South Sudanese troops in Heglig, hundreds of kilometres (miles) to the east in South Kordofan.
Source: AFP Global Edition