The Rwanda Defense Force reported escorting hundreds of "Romanian mercenaries" out of the Democratic Republic of the Congo after seizing Goma.

Rwandan President Paul Kagame has lashed out at South African counterpart Cyril Ramaphosa, after Ramaphosa accused Rwanda of backing the M23 rebels behind the escalating crisis in the eastern Democratic Republic of Congo this week.

U.S. Secretary of State Marco Rubio called for a urgent cease-fire in the conflict in eastern Democratic Republic of Congo saying Washington was "deeply troubled" by a recent escalation in the fighting.

M23 rebels captured the key city of Goma in the eastern DRC Monday, forcing thousands of civilians to flee in the latest in a series of advances - Anadolu Ajansı

Rwanda's government, led by President Paul Kagame, has been accused by the DRC and various international organizations of supporting M23, including providing military assistance, training, and logistical support.

M23 rebels, with support from Rwandan troops, marched into Goma earlier this week and are now advancing south toward Bukavu.

In 2012, when M23 rebels appeared poised to seize control of a major city in eastern Congo, western countries suspended aid to put pressure on Rwanda to withdraw its support.

Nearly 300 foreign mercenaries hired by the Democratic Republic of Congo government to counter a swift offensive by Rwandan-backed M23 rebels in the east have surrendered and were on their way home on Wednesday.

The Rwandan-backed armed group M23 moved south as it closed in on a key military airport in DR Congo on Friday, a day after pledging to take the capital Kinshasa and as international criticism mounted.

The ongoing crisis in the DRC, particularly the escalating tensions in Goma, brings to mind the tireless diplomatic efforts of Tanzanian statesman Dr Salim Ahmed Salim.

Rwanda says it is open to talks with Pretoria over a fallout regarding Rwanda's involvement in conflict in the DRC which has claimed the lives of 13 South African soldiers. This comes as South Africa's armed forces and defence industry leaders rally to raise funds for the families of the fallen troops.