"We are now going to Kinshasa. No one will divide this country," said Col. Vianney Kazarama, the M23 spokesman, to a cheering crowd of thousands.
The rebels organized the rally at Goma's Stadium of Volcanoes after seizing control of the strategic city in eastern Congo Tuesday.
Kazarama first welcomed the crowd in Swahili by shouting "Goma Jambo !" meaning "Hello Goma!"
Kazarama said the M23 rebels' next goal is Bukavu, the capital of South Kivu province on the other side of Lake Kivu. He claimed the rebels already control the town of Sake, 27 kilometers (17 miles) from Goma on the road to Bukavu, and will soon take Minova, a lakeside town in South Kivu.
More than 2,100 army troops and 700 police turned in their weapons, according to M23's Col. Seraphin Mirindi. The former army troops and policemen piled up their arms and ammunition in the stadium.
In Bukavu people are already demonstrating against the Kinshasa government and in support of the rebels, according to local residents reached by phone.
The Congo soldiers remaining in the government army near Goma said they are not sure what to do.
"We are waiting for orders now. We don't know what we are supposed to do. It's hard. My comrades who defected in Goma, we're going to fight them," said a Congolese army major reached by phone in Kanyabayonga, 106 kilometers (66 miles) to the south, where the troops have regrouped. The major required anonymity because of the uncertain situation.
In neighboring Uganda, Congo President Joseph Kabila met with Rwanda President Paul Kagame, for emergency talks prompted by the fall of Goma and the progress of the M23 rebels. Rwanda is blamed for backing the M23 by Congo and by the United Nations.
The talks between Kabila and Kagame are being mediated by Ugandan President Yoweri Museveni, according to a top Ugandan diplomat with knowledge of the talks, who insisted on anonymity because he was not authorized to give information about the talks. Kabila may be compelled to enter into direct negotiations with M23 rebels, said the diplomat. Kabila had previously rejected talks with the M23, but that was before they seized Goma.
"We take it as an emergency meeting," said the diplomat of the talks. "President Kabila is the one who sought the meeting with President Kagame. Museveni had been pressing them to talk. We believe that this is the last chance to solve this thing. The time has come for Congo either to talk or fight (the rebels). You can't do both."
The United Nations accuses the M23 of grave crimes including recruiting child soldiers, summary executions and rape, according to an experts report to be released on Friday.
The United Nations peacekeepers, known by their acronym MONUSCO, did not help the Congo government forces during Tuesday's battle because they do not have a mandate to engage the rebels, said Congolese military spokesman Olivier Hamuli, who expressed frustration over the lack of action by the peacekeepers.
A U.N. spokesman in New York said that the nearly 1,500 U.N. peacekeepers in Goma held their fire to avoid triggering a battle. The peacekeepers "cannot substitute for the efforts of national forces" in Congo, said spokesman Eduardo del Buey.
On Wednesday the Security Council will review the mandate of the U.N. peacekeeping force in Congo. A resolution adopted Tuesday by the Security Council asks the U.N. secretary-general to recommend possible redeployment, and possible "additional force multipliers."
The resolution approved unanimously by the council imposes targeted sanctions, including a travel ban and assets freeze on the M23 rebel group leadership. But it did not name two countries accused by Congo of supporting the rebels: Rwanda and Uganda.
The council demanded that the M23 rebels withdraw from Goma, disarm and disband, and insisted on the restoration of the crumbing Congolese government authority in the country's turbulent east.
The resolution also calls for an immediate end to external support to the rebels and asks the U.N. secretary-general to report on the allegations of foreign support while expressing its readiness to take appropriate measures.
The rebels are believed to be backed by Rwanda, and to a smaller extent by Uganda, which are accused of equipping them with sophisticated arms, including night vision goggles and 120 mm mortars. Evidence is mounting of the involvement by the neighboring country and on Friday, the United Nations Group of Experts is expected to release its final report, detailing the role the neighboring nations played in the recruitment, financing and arming of the rebel movement, which was launched in April.
Associated Press reporter Rodney Muhumuza in Kampala, Uganda contributed to this report.