Who are M23 rebels and why is there fighting in eastern DRC?

The armed group M23 and Rwandan soldiers entered the centre of Goma last Sunday after weeks of advancing on the main city in the Democratic Republic of the Congo's North Kivu province.

- Carlos Mureithi

The advance risks sparking a broader war between Rwanda and DRC and has intensified a humanitarian crisis in the province. It was not clear early this week how much of Goma was controlled by the rebels, but witnesses in the city said rebel fighters could be seen in the centre.

Residents said gunfire could be heard near the airport, city centre and near the border with Rwanda.

What is M23?

M23, or the March 23 Movement, is one of more than 100 armed groups fighting Congolese forces in the mineral-rich eastern DRC. It is present in North Kivu province in areas bordering Rwanda and Uganda and has more than 8,000 fighters, according to the UN.

It is named after the date in 2009 of the signing of an accord between the National Congress for the Defence of the People (CNDP), a Tutsi-led rebel group, and the Congolese government to end a revolt led by the Tutsi people in eastern DRC.

Why is M23 fighting Congolese forces?