GOMA, Democratic Republic of Congo (Reuters) -Congolese rebels said on Sunday they had taken Goma, the biggest city in the east of the mineral-rich country, after a lightning advance that has forced thousands of people to flee and fuelled concerns of a regional war.

The Democratic Republic of Congo’s Foreign Minister warned Sunday that an “attack of unprecedented intensity is taking place in plain sight of the world” as rebel forces and allied Rwandan forces entered the outskirts of Goma.

Fighting has escalated sharply in recent weeks in eastern Congo, where rebels have seized key towns and are closing in on the city of Goma, the government’s last stronghold in the North Kivu province,

Gunshots rang out Sunday night in Goma city centre, in eastern Democratic Republic of Congo, besieged by a militia with the Rwandan army's backing, according to AFP reporters.

Tens of thousands of people are fleeing towns in the Democratic Republic of Congo's east, as rebel forces close in on the city of Goma. Explosions and gunshots were heard in city - home to more than a million people - late on Sunday evening, according to local media reports.

The Democratic Republic of Congo (DRC) has severed diplomatic ties with Rwanda, accusing it of fuelling the rebellion. At least 13 soldiers serving with peacekeeping forces in the DRC have been killed in clashes with M23 rebels,

STORY: Rwandan-backed fighters on Sunday closed in on eastern Congo's largest city of Goma……forcing thousands of civilians to flee, and grounding flights from the local airport as government forces battled to stop the rebels from seizing the city.

In a tit-for-tat action, the Democratic Republic of Congo and Rwanda are recalling diplomats from each other's capitals. The actions come amid intense fighting between Congolese forces and Rwandan-backed fighters in the eastern Democratic Republic of Congo,

M23 rebels claim they have taken control of the city of Goma in the Democratic Republic of Congo. The UN has condemned 'flagrant disregard' for the DRC's sovereignty. DW has more.

Gunfire broke out on Sunday night in the centre of the besieged Congolese city Goma after the Democratic Republic of Congo accused neighbouring Rwanda of sending more troops across the border to help pro-Kigali fighters capture the provincial capital.

Congolese rebels and allied Rwandan forces entered the outskirts of Goma on Sunday and the airport in the key eastern city was no longer in use, the top UN official in the country said. Thousands fled the fighting that also killed at least 13 peacekeepers.