NEW : The United Nations calls on rebels to stop fighting . -- UN Secretary General Ban Ki-moon says the world must act now or face a "humanitarian catastrophe. The M23 group was named for a peace deal reached on March 23 , 2009 , which it accuses the government of violating . " African leaders gave the rebel group until midnight Tuesday to withdraw . The rebels want to talk with Congolese president about breaches of a 2009 peace treaty .
NEW : The United Nations calls on rebels to stop fighting . -- UN Secretary General Ban Ki-moon says the world must act now or face a "humanitarian catastrophe." African leaders gave the rebel group until midnight Tuesday to withdraw . The rebels want to talk with Congolese president about breaches of a 2009 peace treaty .