By Michelle Nichols and Louis Charbonneau
UNITED NATIONS (Reuters) - U.N. peacekeepers in the Democratic Republic of Congo have witnessed shelling into Rwanda by M23 rebels over the past week and have not observed any firing across the border by the Congolese army, the United Nations said on Thursday.
Rwanda accused its Central African neighbor earlier on Thursday of persistently shelling into its territory and said such "provocation" could no longer be tolerated, after a flare-up of fighting in Congo's war-torn east.
Deputy U.N. peacekeeping chief Edmond Mulet briefed the U.N. Security Council on the situation and said the U.N. mission in Congo - known as MONUSCO - has seen only M23 rebels shelling into Rwanda, according to Deputy French Ambassador Alexis Lamek.
"Mr Mulet explained that actually the only acts of shelling witnessed by MONUSCO towards the Rwandan territory ... do come from M23," Lamek told reporters after the briefing.
Rwanda's deputy U.N. ambassador, Olivier Nduhungirehe, was adamant that the shelling had been carried out by Congolese troops and questioned how the U.N. peacekeepers could have concluded so quickly that M23 rebels were to blame.
"We are sure that the bombs are coming from the FARDC," he told reporters, referring to the Congolese army, but he added that Rwanda was calling for an independent investigation to "convince the international community."
U.N. experts and Congo have accused Rwanda of supporting M23, a claim Kigali rejects. The cross-border accusations underscore the M23 rebellion's roots in a web of local politics and regional conflicts over ethnicity, land and minerals.
It was not immediately clear what motive M23 would have for firing into Rwanda.
U.N. spokesman Farhan Haq said U.N. peacekeepers had not seen the Congolese army firing into Rwanda during the past week.
The U.N. Security Council condemned the resumption of fighting in eastern Congo in a statement on Thursday and also "expressed concern at reports of repeated mortar shells and bombs from DRC territory landing in Rwandan territory."
It called for a "thorough investigation into the sources of these shells and bombs by the Expanded Joint Verification Mechanism," a regional body created to investigate incidents between the two countries.
The statement was agreed after several days of diplomatic wrangling during which Rwanda repeatedly blocked proposed language and pushed for it to specify, among other things, that shells landing in its territory had come from Congo.
BAN SPEAKS WITH KAGAME
Mulet told the council on Thursday that there were consistent reports of external support for M23 and that peacekeepers had gathered credible reports of Rwandan troops crossing into Congo, said a council diplomat present at the briefing, speaking on the condition of anonymity.
Mulet said U.N. Secretary-General Ban Ki-moon had spoken with Rwandan President Paul Kagame to urge restraint, the diplomat said.
Rwanda accused the Congolese army of firing a shell that killed a woman and seriously wounded her two-month-old baby in a market in Rubavu town on Thursday morning, followed by a second shortly after that wounded another person.
The U.N. special envoy to Congo, Martin Kobler, and the commander of MONUSCO are visiting Rwanda "to clarify matters as they continue to urge all sides for maximum restraint" over the cross-border shelling incidents, Haq said.
One U.N. peacekeeper from Tanzania was killed and three other blue-helmeted troops were wounded during fighting in eastern Congo on Wednesday.
Rwanda blocked a joint U.S.-French proposal to impose U.N. sanctions on two senior M23 commanders, arguing that the evidence against the men was weak, Rwandan and other U.N. envoys said on Wednesday.
Nduhungirehe, the Rwandan deputy ambassador, told Reuters that Kigali blocked the proposed blacklisting because it would have undermined regional efforts to bring peace to eastern Congo and Kampala talks between M23 and Congo's government.
A 3,000-strong U.N. intervention brigade, with a tough new mandate to protect civilians and neutralize armed groups in Congo, sprang into action last week after it accused the M23 rebels of shelling the eastern city of Goma.
(Editing by Mohammad Zargham)