Nkunda's forces attacked the FARDC (the Congolese army) before dawn this morning at Katale, a town just south of Masisi, 60 kilometers to the northwest of Goma. Reports say that somewhere between 1,000 - 2,500 men were involved in the offensive, with the goal of taking the headquarters of FARDC's Charly brigade, where 1,000 FARDC troops are posted. The fighting lasted 5-6 hours, and Charly brigade managed to hold onto Katale. No doubt they had plenty of assistance from MONUC.
We've been expecting this for months, and tensions have been so high in the last week or so that it's not really surprising. I believe that the government wanted Nkunda to attack before being attacked such that MONUC would be forced to help FARDC defend their positions. FARDC isn't capable of singlehandedly taking out Nkunda's forces. So, in a great example of the sometimes bizarre logic of central Africa, being attacked this morning may have been exactly what Kabila wanted. As the FARDC's army operations coordinator for North Kivu told Reuters, "We are taking steps this time to finish with this situation, which is beginning to make us look ridiculous."
Reports say that FARDC claims that reinforcements are on the way. There are also reports that virtually all of Masisi's residents fled. Xinhua and at least one Congolese news outlet report that Rubaya is under Nkunda's control.