Troops sent in to reinforce Goma
10 July 2012 Last updated at 21:48 BST
The government of the Democratic Republic of Congo has expressed alarm as rebel forces advance towards the country's main eastern city of Goma.
Government and UN troops are being sent to reinforce the city as Rwanda is accused of supporting the M23 rebels, a claim denied by the Rwandan government.
Thousands of refugees have fled into neighbouring Uganda to escape the violence.
The BBC's Mike Wooldridge reports.