Creating a robust force from the disparate elements of the UN contingent is not proving easy
By David Loyn
International development correspondent, BBC News
The UN peacekeeping force in the Democratic Republic of Congo is already the largest, most expensive and most muscular of its kind anywhere in the world, but its troops have been unable or unwilling to prevent civilians from being killed in the worsening conflict.
It was sent under the UN's strongest possible mandate - Chapter Seven - giving the soldiers in it the right to use "all necessary means" - that is, lethal force, to impose their will.
The call for 3,000 extra troops, made by the UN Secretary General Ban-Ki Moon, comes six weeks after an urgent appeal for that number of troops came from the civilian head of the mission on the ground, Alan Doss.
During that time security became far worse.
Several thousand people have been forced from their homes and from resettlement camps, and many have been killed, including at least 26 earlier this month in Kiwanja.
This incident was called a war crime by UN observers, and yet it happened virtually within sight of a UN military base.
The force is drawn from 18 nations. The largest contingent, more than 4,000 troops, comes from India, one of the more competent armies in the world.
India's South Asian neighbours - Bangladesh, Pakistan and Nepal - are the only other countries with more than 1,000 troops in the UN force.
FORCES AROUND GOMA
CNDP: Gen Nkunda's Tutsi rebels - 6,000 fighters
FDLR: Rwandan Hutus - 6,000-7,000
Mai Mai: pro-government militia - 3,500
Monuc: UN peacekeepers - 6,000 in North Kivu, including about 1,000 around Goma (17,000 nationwide)
DRC army - 90,000 (nationwide)
Source: UN, military experts
The contributions from other countries go down to six soldiers from Serbia.
Knitting this disparate group of nations into a force that is robust enough to deal with the challenges of DR Congo has proved a hard task.
Although the UN secretary general has belatedly responded to the request by his representative on the ground to send more, it is hard to see where extra forces would come from.
In August Mr Doss denied suggestions made in an Oxfam report that his forces were not making the protection of civilians their priority.
And he said that there was no inconsistency between this and the efforts of the force to bring an end to the fighting and persuade troops to lay down their arms.
The weakness of the force comes partly from its size - around 16,500 troops - outnumbered 1,000 to 1 by the civilian population in a huge region where roads are poor.
'Doomed to fail'
Opposing it are a bewildering array of rebel forces, driven by ethnic hatred and a desire for a share of the huge mineral wealth available in the region.
The largest rebel forces are much better motivated and equipped than government forces.
The failure of government forces was one of the factors that appears to have been behind the resignation of the Spanish commanding officer of the UN force.
General Vicente Diaz de Villegas pulled out after less than two months in the job just as the fighting intensified late last month.
He has not spoken publicly but sources quoted by a Rwandan newspaper which first reported his resignation say that he believed the UN military mission was ''doomed to fail''.
Supporters of the mission point to its successes until this year, and its successful defence of Goma, a prize that is clearly a target of the rebels.
But the wider aims of the mission, in disarming and re-integrating rebel forces into a joint defence force for the region have been sidelined as the war intensifies.