Rebel fighters in the Democratic Republic of Congo have threatened to march to the capital, Kinshasa, after capturing the eastern city of Goma.
M23 rebel commander Lt Col Vianney Kazarama told a crowd in Goma that they were ready to “liberate” the country.
The UN Security Council has strongly condemned Goma’s seizure and called for sanctions against the rebels.
Meanwhile, DR Congo’s President Joseph Kabila is holding crisis talks with his Rwanda and Ugandan counterparts.
The rebel threat has renewed fears that the 1997-2003 war in DR Congo, during which some five million people died, could reignite, analysts say.
Last month, a UN panel of experts accused Uganda and Rwanda, both neighbours of DR Congo, of backing the M23 rebel group.
On Tuesday, the rebels entered Goma, the main city in eastern DR Congo with a population of about one million, after facing little resistance from government and UN troops.
The BBC’s Gabriel Gatehouse says Lt Col Kazarama addressed a crowd at a football stadium in the city.
“Do you want us to march to Kinshasa?” he said, as the crowd shouted back: “Yes”.
Our reporter says policemen in Goma have also been handing in their weapons as demanded by the M23 rebel group, which was formed in April following an army mutiny.
The UN has said it has received reports that the rebels have abducted women and children from Goma. Killings and looting have also been reported.
Lt Col Kazarama said that “the journey to liberate [DR] Congo has started now”.
“We’re going to move on to Bukavu and then to Kinshasa,” Reuters news agency quoted him as saying.
Kinshasa is about 1,600km (1,000 miles) from Goma.
The UN Security Council adopted unanimously a resolution condemning the rebel seizure of Goma and calling for sanctions against M23 leaders
While the Security Council had earlier this month ordered sanctions against M23 leader Sultani Makenga, the new resolution calls on the UN sanctions committee to review urgently the cases of other M23 figures, including Innocent Kaina and Baudouin Ngaruye.
In its resolution, the Security Council demanded an end to foreign support – seen as a reference to Rwanda and Uganda – for the rebels.
However, both countries have persistently denied that they are arming the rebels.
President Kabila has been in the Ugandan capital, Kampala, since the fall of Goma, holding talks with his Rwandan and Ugandan counterparts, Paul Kagame and Yoweri Museveni respectively, in an attempt to diffuse the crisis.
‘Lies and propaganda’
He has urged the Congolese nation to “resist” the rebels and said “war had been imposed” on the country.
The UN has a 19,000-strong force in DR Congo, known by its acronym Monusco, to support the government.
French Foreign Minister Laurent Fabius has described as “absurd” the UN’s failure to intervene in Goma, calling for a change in its mandate.
But a UN spokesman said that with only 1,500 peacekeepers in Goma a “value judgement” had to be made.
“Do you open fire and put civilians at risk or do you hold your fire, continue your patrols, observe what is happening and remind the M23 that they are subject to international humanitarian and human rights law?” the spokesman said.
President Kabila took power following the assassination of his father, Laurent, in 2007.
About a decade earlier, Laurent Kabila had taken power in Kinshasa after marching from the east with rebel forces backed by Rwanda and Uganda.
Mr Kabila later fell out with his regional allies.
Col Makenga told the BBC French Service that it was absurd to believe that Rwanda was backing his rebellion.
“It’s a lie, it’s Kinshasa propaganda. Kinshasa can talk a lot so when they’re feeling the heat they try to defend themselves and that’s why they say Rwanda, they say Uganda, tomorrow they will say United States or England – that’s how it is,” he said.