U.N. experts accused the Rwandan military of commanding Congolese rebel forces in their recent capture of the strategic city of Goma, saying a top Rwandan commander traveled to Congo to oversee the offensive and hundreds of Rwandan troops fought alongside the M23 rebel fighters.

In a letter to a U.N. Security Council committee, the experts provided a day-by-day outline and photos backing their conclusion. The M23 rebels held Goma, a provincial capital of 1 million, for two weeks before Congolese soldiers took back control Monday.

The letter, obtained Tuesday by The Associated Press, is a follow-up to a report preceding the capture of Goma that made similar accusations against Rwandan forces.