The United Nations Security Council has voted to send 3,000 more troops to the Democratic Republic of Congo following renewed fighting in the country's east.
The increase means the peacekeeping mission, Monuc, will have about 20,000 troops and police on the ground - the biggest UN force of its kind.
But correspondents say diplomats admit they do not know where the troops will come from, or when they will be sent.
Clashes between the army and rebels have created a humanitarian crisis.
An estimated 250,000 people have been forced to flee their homes in recent months.
The rebels led by Gen Laurent Nkunda withdrew from positions north of the city of Goma on Wednesday to allow aid into the area.
The withdrawal followed several weeks of fierce fighting, and came after weekend talks with the UN envoy, Olusegun Obasanjo.
The BBC's Laura Trevelyan at the UN says the Security Council, which first received the request for reinforcements six weeks ago, voted unanimously to send 2,785 more troops and 300 police officers.
Our correspondent says Monuc has been criticised for not doing enough to protect people from rebels while the army was in retreat.
She says UN commanders on the ground will be told that they can use all means necessary to protect the local population.