U.N. peacekeepers in Democratic Republic of Congo are investigating the Congolese allegation that Rwandan army troops this week crossed into North Kivu province to help insurgents led by renegade Tutsi General Laurent Nkunda.
Rwanda has denied the accusation but Congo has asked the U.N. Security Council to hold an emergency meeting on the alleged incursion. The war of words has stoked fears of an escalation of Nkunda's rebellion into a wider conflict between the two Great Lakes neighbours, who have fought in the past.
"We will certainly do everything we can to prevent that from happening," Alan Doss, head of the U.N. peacekeeping mission in Congo (MONUC), told Reuters.
"I think we all have to do all we can to lower tensions and find ways to renew a constructive dialogue," he said.
At 17,000-strong, MONUC is the world's biggest U.N. peacekeeping mission. The force is checking if Rwandan army regulars are inside North Kivu.
Doss told Reuters this was not easy in a porous, volatile and geographically rugged border area where ethnic lines are blurred. Nkunda's rebels wear Rwandan uniforms and speak Kinyarwanda, a language used on both sides of the border.
"These are difficult areas. We're not talking about walking down a main street here," Doss said.
For more than a decade, eastern Congo has been a tinderbox of ethnic tensions that grew out of Rwanda's 1994 genocide.
Rwanda has twice invaded Congo, including a major intervention during the 1998-2003 war. The war and the humanitarian crisis it sparked have claimed an estimated 5.4 million lives, mostly from hunger and disease.
AU Peace Mission
Analysts said there was evidence of strong links between Rwanda and Nkunda's CNDP rebels, but direct Rwandan army involvement in North Kivu was more difficult to prove.
"We have documented in the past a degree of Rwandan support for the CNDP, including recruitment in Rwandan refugee camps," Human Rights Watch Congo researcher Anneke Van Woudenberg said.
"But we have received no information indicating a significant presence of Rwandan troops in eastern Congo."
African Union (AU) Commission chief Jean Ping was due in Kinshasa on Friday to try to defuse the row with Rwanda.
Nkunda's rebels said on Wednesday they had captured a government army base at Rumangabo, 40 km (25 miles) north of Goma. The fighting there killed or wounded dozens of Congolese soldiers, according to the United Nations.
Congo blamed the Rwandan army for the attack. The rebels left the base and by Friday Congo's army was back in control.
Congo wants Rumangabo to be investigated by a team of both Congolese and Rwandan representatives, overseen by MONUC.
Kinshasa has urged MONUC to be more active in fighting the insurgency led by Nkunda, who says he is fighting to protect the country's Tutsi minority from Rwandan Hutu rebels.
Rwanda accuses the Congolese army of collaborating with the Hutu rebel Democratic Forces for the Liberation of Rwanda (FDLR) in their fight against Nkunda. Kinshasa denies this.
MONUC chief Doss has asked the U.N. Security Council for more troops to confront the worsening situation in North Kivu, where fighting has intensified since late August following the collapse of a January peace accord.
"Perhaps this last investment, and I hope it is that, will then give the country a more secure future," Doss told Reuters.
