Angola says it will send a military unit to eastern Democratic Republic of Congo, days after a truce it brokered failed to end fighting.
Both sides in the conflict – the M23 rebels and government troops – have accused each other of breaking the ceasefire that began on Tuesday.
An East African force was also recently deployed to the area, which is rich in minerals and has dozens of militias.
The UN says the conflict forced 300,000 people from their homes last month.
This happened in North-Kivu province, which borders Rwanda and Uganda, and is a fertile and mountainous area long plundered by rival groups.
There is increasing concern about the humanitarian crisis caused by the fighting, which was still ongoing on Friday.
The European Union has just started an operation to fly in aid to the regional capital, Goma, saying humanitarian agencies have become overwhelmed.
A statement from the Angolan president’s office said the soldiers would be deployed to help secure areas that have been held by the M23 rebel group and to protect ceasefire monitors.
Kenyan soldiers, who are part of the East African Community Regional Force, have deployed to these areas too.
The rebels, who are widely reported to be backed by Rwanda, had just hours earlier said they would withdraw from several captured villages.
The Congolese government will welcome the arrival of Angolan troops to help in the fight against the rebels.
But there is a danger of this becoming a wider international conflict.
More than 20 years ago the armies of at least eight African countries fought a war in eastern DR Congo, dubbed “Africa’s world war”, that caused immense suffering for the civilian population.
Rwanda has for many years criticised the Congolese authorities for failing to disarm Hutu rebels – some of whom are linked to the Rwandan genocide in 1994.
It denies backing the M23, which has captured vast swathes of territory over the past year and has been advancing towards Goma.
A decade ago, M23 fighters also captured large parts of North Kivu – but were eventually routed by UN and regional troops and as part of a peace deal disarmed.
They began regrouping early last year.
Largely made up of Congolese army deserters, they first took up arms in 2009 accusing the government of marginalising the country’s ethnic Tutsi minority and failing to honour previous peace accords.
