Rebels who seized Goma in the Democratic Republic of Congo have rejected calls to withdraw from the city and have demanded talks with Congolese President Joseph Kabila.

The head of the M23 rebel group's political arm (Bishop Jean-Marie Runiga) told Reuters the rebels “will stay in Goma, waiting for negotiations.”

On Wednesday, Mr. Kabila issued a joint statement with Rwandan President Paul Kagame and Ugandan President Yoweri Museveni calling on the rebel group to stop its offensive and pull out of Goma. They also said the DRC government has promised to examine the causes behind the conflict.

The Ugandan and Rwandan presidents voiced support for the DRC government, which the rebels on Wednesday vowed to overthrow.

The DRC has accused both Rwanda and Uganda of supporting M23, an allegation both countries deny.

M23 rebels held a rally at a Goma stadium on Wednesday, a day after capturing the town, a provincial capital on the Rwandan border. Spokesman Vianny Kazarama said the rebels plan to keep on moving.

Hundreds of Congolese police and troops surrendered their weapons at the rally.

Kazarama said the rebels' next goal is Bukavu, 100 kilometers to the south. He said the group already controls the town of Sake, also south of Goma, and plans to eventually reach Kinshasa, the capital, more than 1,500 kilometers to the west.

Also Wednesday, the top U.N. official in the DRC, Roger Meece, said the rebels are executing local leaders in Goma who resist the group's authority. The rebels have yet to respond to U.N. accusations of human rights abuses.

The U.N. Security Council voted unanimously Tuesday to impose sanctions against M23 leaders. The French-sponsored resolution demands that the rebels immediately pull out of Goma, located on the Rwandan border, and condemns all foreign support for the group.

On Tuesday, M23 fighters seized Goma with no resistance, after Congolese troops fled and 1,500 U.N. peacekeepers stood by.