UN Secretary-General Ban Ki-moon has warned that escalating violence in eastern Democratic Republic of Congo is creating a humanitarian catastrophe.
He said the violence could have tragic consequences for the entire region.
Rebels loyal to renegade General Laurent Nkunda have advanced on the eastern city of Goma, scattering residents and threatening to overwhelm the 17,000-strong UN force, MONUC, which is trying to halt a return to all-out war.
Thousands of civilians and hundreds of Congolese government soldiers have poured into Goma.
In a statement read by UN spokeswoman Marie Okabe, Mr Ban said 'the intensification and expansion of the conflict is creating a humanitarian crisis of catastrophic dimensions and threatens dire consequences on a regional scale'.
Mr Ban urged 'all parties to immediately cease hostilities and to respect international humanitarian law'.
'He deplores the use of civilians as human shields and their deliberate targeting by belligerents,' Ms Okabe said.
Shortly after Mr Ban's statement, a spokesman for Gen Nkunda loyalists said the CNDP rebels had declared a ceasefire.
Rwanda denies supporting rebels
The UN Security Council discussed the issue for the second day in a row yesterday and unanimously adopted a non-binding statement that 'condemns the recent CNDP offensive ... and demands that it bring its operations to an end'.
The UNSC statement also called on the governments of Congo and neighbouring Rwanda 'to take concrete steps to defuse tensions and to restore stability in the region'. It also welcomed Nkunda's ceasefire and urged him to rejoin the peace process.
Several council diplomats told wire services that Rwanda was clearly providing support to Nkunda's CNDP but Rwanda's UN Ambassador Joseph Nsengimana denied the allegation. 'It is not true,' he told wire services. 'There is no proof.'
The council took no action on a request from MONUC chief Alan Doss for a temporary increase in his force by roughly 2,000 personnel - two battalions of soldiers, two companies of special forces and one police unit.
The statement said the council duly noted the request.
British Ambassador John Sawers told reporters the request for additional troops would be discussed in the coming weeks, above all by the EU. In the short term, he said MONUC would be redeploying peacekeepers to reinforce the roughly 800 MONUC troops now in Goma.
In an attempt to mediate the crisis on Congo's border with Rwanda, Ms Okabe said Mr Ban was dispatching two envoys to meet the governments, deputy UN peacekeeping chief Edmond Mulet to Congo and UN special envoy to Zimbabwe Haile Menkerios to Rwanda.
Mr Ban's decision to send Mr Menkerios to Kigali reflects a growing concern among UN officials that Rwanda may be providing support to Nkunda, as Congo has alleged for weeks.
Ms Okabe said both sides in the fighting were preventing UN peacekeepers from evacuating civilians.
The UN refugee agency said up to 45,000 uprooted people had left camps for the displaced and headed to Goma yesterday.
The UNHCR also said more than 1,000 villagers fled to neighbouring Uganda, with many more expected to follow.
