The United Nations Security Council has unanimously agreed to expand the UN peacekeeping force in the Democratic Republic of Congo by 5,900 troops.
A rapid reaction force is expected to be based in the east
The mandate of the force, currently 10,800-strong, has also been extended until the end of March 2005.
But the boost in numbers is less than half the amount requested by UN Secretary-General Kofi Annan.
Most of the new troops will be deployed to the volatile east of the country, the scene of continuing instability.
After the Security Council's vote, Mr Annan said he still believed a force of 23,900 was the "minimum required to meet the current challenges in the DRC" - a country recovering from five years of war in which some three million people died..
He said he hoped the council "will favourably" consider the full request at a later date.
United States envoy to the UN, Stuart Holliday, had defended the numbers of peacekeepers being deployed.
"We think that keeping the numbers in that range is what's necessary to meet the actual mission task," he said.
Correspondents say the US has not been alone in expressing concern about the growing challenges of UN peacekeeping missions, with cost as much an issue as finding nations willing to contribute forces.
A battalion of some 700 soldiers is expected to be based in the east of the country as a rapid reaction force.
'No state control'
In June, anti-UN protests swept the country after the UN failed to prevent the brief capture of the eastern town of Bukavu by rebels.
Meanwhile, a report says an arms embargo in the east has been violated and is undermining the peace process, reports Reuters news agency.
"Lack of state control in the east of the country means few border controls, no airspace control, and no administrative control," the British parliamentary group report says.
A resident in the eastern town of Goma, where armed groups have recently been vying for control of mines, says more peacekeepers are needed.
"I think it isn't enough because of the problems we have, especially in Kivu province. They should double the troops, even triple them. That would be good for peace," Alan Awasi told the BBC's Network Africa programme.
However, he said the integration of the army need to be speeded up "to reduce the flow of weapons and reduce the possibility of conflict".