* Days of shelling kill at least six civilians this week
* Congo accuses Rwanda of sending troops to support rebels
* Kigali accuses Congo army of shelling Rwandan villages (Adds U.N. spokesman quotes, injured peacekeepers, protest details)
By Kenny Katombe
GOMA, Democratic Republic of Congo, Aug 24 (Reuters) - S hells fired by M23 rebels killed at least three people in Congo's eastern ...