What you need to know:
- The M23 group emerged out of a 2013 ethnic Tutsi Congolese rebellion that was supported by neighbouring Rwanda and Uganda at the time.
A top UN official has accused the M23 militia force active in the Democratic Republic of Congo of attacking peacekeepers in the troubled east of the country.
The accusation by Assistant Secretary General Bintou Keita came after the DR Congo's army launched an offensives against the group on Thursday.
Keita on Sunday condemned the militia's attack on both the government forces and the UN's Monusco peacekeeping force.
"The rebels of the M23 deliberately targeted the peacekeepers of Monusco... who fired back, in line with their mandate," she said in a statement.
The army and the Monusco soldiers then launched a joint operation against the rebels, her statement added.
Residents of Goma, the main city in North Kivu province, said Monusco had used helicopters in their operation against the rebels.
A statement from the M23 force said their fighters had forced the government to retreat and they had taken refuge at a Monusco base, thus forcing the peacekeepers to intervene.
The M23 group emerged out of a 2013 ethnic Tutsi Congolese rebellion that was supported by neighbouring Rwanda and Uganda at the time.
They resumed fighting earlier this year, accusing the government of having failed to respect a 2009 agreement under which their fighters were to be incorporated into the army.