* Fighting escalates in eastern Congo, peacekeeper killed
* Rwanda blocks UN statement condemning M23 attacks
* Rwanda says hopes amended statement will be approved
By Louis Charbonneau
UNITED NATIONS, Aug 28 (Reuters) - Rwanda blocked a joint U.S.-French proposal to impose U.N. sanctions on two senior commanders in the M23 rebel group in eastern Congo, arguing that the evidence against the men was weak, Rwandan and other U.N. envoys said on Wednesday.
The latest diplomatic wrangling in New York came as U.N. helicopters and artillery attacked M23 rebel positions near the city of Goma in eastern Democratic Republic of Congo on Wednesday in support of an offensive by the Congolese armed forces. One U.N. peacekeeper from Tanzania was killed and three other blue-helmeted troops were wounded.
The United States and France submitted documents to the U.N. Security Council's Congo sanctions committee last week explaining why M23's Colonel Vianney Kazarama, military spokesman for the rebel group, and Erick Mboneza, an M23 commander, should be hit with U.N. sanctions.
Among other things, those documents, seen by Reuters, cite a July Human Rights Watch report that accused Mboneza of ordering the summary execution of a 24-year-old man he said was a thief.
The documents also refer to a U.N. Group of Experts report that says Mboneza and an M23 Colonel Kaina, who is already subject to a U.N. travel ban and asset freeze for his activities in the rebel group, were seen meeting with Rwandan military officers between March and May 2013.
The Group of Experts has repeatedly accused Rwanda of supporting M23, an allegation Kigali vehemently rejects. The cross-border accusations underscore the M23 rebellion's roots in a complex web of local politics and regional conflicts over ethnicity, land and minerals.
Rwanda's deputy U.N. ambassador, Olivier Nduhungirehe, 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.
He added that the evidence supporting the U.S.-French proposal was "very poor."
Diplomats said Rwanda, a temporary council member, was the only one of the 15 member nations that opposed the idea of blacklisting the two men.
The Security Council's sanctions committee works on the basis of consensus, which means Rwanda was able to singlehandedly block the proposed blacklisting.
In theory, council members could vote on the blacklistings in a Security Council resolution that Rwanda would be unable to block. It was not clear if the council was prepared to do that.
Separately, Rwanda has repeatedly rejected council efforts to issue a public statement condemning M23 attacks on U.N. peacekeepers last week, U.N. diplomats said. Rwanda complained that the Western-drafted statement was unbalanced and unfairly targeted the M23 while ignoring attacks by the Congolese army.
Kigali initially criticized the statement for not mentioning shelling onto Rwandan territory last week, though later drafts, all seen by Reuters, did ask for the council condemn the firing into Rwanda.
A new draft of the statement was rejected by Rwanda on Wednesday. A Rwandan delegate said in an email to other Security Council members that it could not support some of the language in the latest draft text.
One council delegation responded to the Rwandan rejection by saying , "It would be the first time when attacks on U.N. peacekeepers are not condemned by the Security Council. This situation is deeply regrettable," according to a copy of the email, seen by Reuters.
But Nduhungirehe said negotiations on a statement were continuing. "We are now close to an agreement," he said.
A 3,000-strong U.N. intervention brigade, with a tough new mandate to protect civilians and neutralize armed groups in the mineral-rich central African nation, sprang into action last week after it accused the M23 rebels of shelling Goma. The violence has been escalating there in recent days. (Reporting by Louis Charbonneau; Editing by Cynthia Osterman)