U.S. President Donald Trump on Thursday described the crisis between Rwanda and Democratic Republic of Congo as a "very serious problem."

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.

Britain has warned Rwanda that its involvement in an escalating conflict in the Democratic Republic of Congo could jeopardise the over $1 billion of aid it receives every year.

The Rwanda-backed armed group M23 vowed on Thursday to march on the DR Congo capital, Kinshasa, as its fighters made further advances in the mineral-rich east of the country. "We will continue the march of liberation all the way to Kinshasa,

The Council met on Tuesday for the second time in three days to discuss the escalating crisis in the eastern Democratic Republic of Congo.

Kenya has announced a virtual crisis summit, but Congolese state media says President Felix Tshisekedi will not attend.

Congo's security forces are fighting against Rwanda-backed rebels who advanced into a key eastern city in a major escalation of a decadeslong conflict.

There was gunfire Tuesday in the eastern Democratic Republic of Congo city of Goma, as the United Nations warned of a worrying humanitarian situation amid clashes between Congolese soldiers and Rwandan-backed rebels who attacked the area and claimed to be in control.

The United Nations expressed deep concern at reports of M23 rebels and Rwandan troops advancing south towards the Congolese city of Bukavu on Thursday, as the militants sought also to assert their control over east Congo's largest city Goma.

Britain, the EU, and the United Nations have piled pressure on the African nation over its backing of the M23 rebels