GOMA, Congo (AP) — A rebel group in Congo that succeeded in overrunning and briefly holding one of the largest cities in the country's east is now accusing the Congolese government of refusing to negotiate at recently-reconvened peace talks in Uganda's capital.

M23 president Bertrand Bisimwa wrote in a letter to the U.N. Secretary-General's special envoy for the Great Lakes region that the rebels also believe the Congolese army and its allies are preparing an imminent attack.

"Government delegates arrived in (the Ugandan capital) Kampala on Wednesday to tell the mediator that they will no longer negotiate with M23," he wrote.

Congolese government spokesman Lambert Mende told The Associated Press on Friday that the mediator had asked both sides to put forth proposals.

"What the government is waiting for now is for the facilitator to deliver to both parties a synthesis of the proposals .... The M23 wants to restart with things that we've talked about for six months. They are trying to buy themselves time," Mende said.

For 10 days last November, the rebel group believed to be financed by neighboring Rwanda invaded the city of Goma, home to around 1 million people and one of the most strategically important cities in Congo.

The rebels agreed to retreat only after forcing the government to agree to talks, which began last December. They broke down in April, ahead of U.N. Secretary-General Ban Ki-moon's visit to Goma, and they were scheduled to restart this week.

Bisimwa's letter adds that the government is rounding up suspected supporters of the M23, especially people with links to Rwanda, which is accused of financing and directing the rebels, according to multiple reports by a panel of United Nations experts.

"In addition, government secret services are arresting a lot of people in Goma (over 50 persons to date), most of whom are Rwandophone people. Some of them have already been transferred to Kinshasa or taken to unknown locations," the letter said.

As for the accusation that government forces are preparing an attack, Mende said the army cannot be criticized for maneuvering on Congolese territory. He denied that security services were targeting Rwandophones for arrest, and said he was not aware of 50 people having been arrested in Goma recently.

"We have nine people who have been transferred to Kinshasa," he said. "Only two of them are Rwandophones."

However, United Nations-backed Radio Okapi in Congo said on Thursday that around 20 people had been arrested in Goma recently on suspicion of collaborating with M23, according to their relatives.

BET Global News - Your source for Black news from around the world, including international politics, health and human rights, the latest celebrity news and more. Click here to subscribe to our newsletter.  

Get ready for the BET Experience, featuring Beyoncé, Snoop Dogg, R. Kelly, Erykah Badu, Kendrick Lamar and many more. Go here for more details and info on how to buy tickets. Sign up now to attend free film screenings, celebrity basketball games and more.

(Photo: AP Photo/Jerome Delay, File)