Goma - United Nations troops in the Democratic Republic of Congo went into action on Friday to battle M23 rebels after at least four civilians were killed in clashes near the flashpoint city of Goma, a UN spokesperson said.
Late Thursday, shells hit the outskirts of Goma, killing a woman and a child, and a rocket struck the nearby village of Kanyaruchinya, killing two and injuring nine others.
The civilians were victims of fighting that has erupted sporadically since mid-July between M23 and the regular army in a region 20km north of Goma, a city of one million people, ending a truce of about two months.
Military spokesperson Prosper Basse told UN-sponsored Radio Okapi that troops of the UN mission in the country (Monusco) were "henceforth engaged alongside the FARDC (regular army)" to deal with the threat.
South African artillery forces in a new UN intervention brigade, authorised in March to take the offensive against armed movements, destroyed a rebel T55 tank stationed near Kibati, about 20km from Goma, according to the UN.
President Jacob Zuma, whose SA National Defence Force has committed 1 345 men to the UN brigade, met in Luanda on Friday with DR Congo President Joseph Kabila and Angola's Jose Eduardo dos Santos to discuss the insurgency.
Dos Santos said the instability threatened "the peace and security of the whole region".
Three months ago, Monusco declared a protection zone with a perimeter of 30 kilometres around Goma and the nearby strategic town of Sake "to prevent this sort of atrocity by M23 against civilian populations", spokesperson Basse said.
M23 issued a statement accusing the regular army and an ethnic Hutu rebel movement based in the region, the Democratic Forces for the Liberation of Rwanda (FDLR), of dropping "several bombs on Rubavu district in... Rwanda and central Goma to get Rwanda and MONUSCO involved in the war".
Congolese army spokesperson Lieutenant-Colonel Olivier Hamuli said on Radio Kivu One that it was "impossible" that M23 shells could "reach Goma because its positions are too distant".
A Congolese military source said that the fighting on the frontlines near the villages of Mutaho and Kibati began on Friday morning, but the sector had since calmed down.
M23 is made up of Congolese Tutsi former rebels who were integrated into the army following a 2009 peace accord. They mutinied in April 2012 saying the agreement was never fully respected by the Kinshasa government.
UN experts have accused neighbouring Rwanda and Uganda of backing the rebel movement, a claim both countries refute.
The insurgents occupied Goma for 10 days last November before withdrawing under international pressure and in return for a dialogue with Kinshasa, which has since stalled.