Rebels appear to be edging closer to taking control of the key city of Goma in the east of the Democratic Republic of Congo following reports that they had captured its airport.

The Congolese government has insisted that it is still in charge as fighting in parts of the city continues. Warehouses with food and medical supplies have been looted, aid agencies say.

The clashes between M23 rebels and the army and its allies have left hospitals overwhelmed by casualties and bodies lying on the streets, according to the UN.

Growing anger over the rebel offensive led to protesters targeting foreign embassies in the capital, Kinshasa. Calls for peace talks to end the fighting are mounting.

Neighbouring Rwanda has been accused of backing the Tutsi-led M23 as it made a rapid advance in recent months across the mineral-rich region.

Rwanda has consistently denied this.

On Tuesday, the new US Secretary of State Marco Rubio urged Rwanda's President Paul Kagame to ensure an immediate ceasefire in DR Congo.

Kagame said in a post on X that they agreed on the need for a ceasefire and address the "root causes of the conflict".

Kenya's President William Ruto has said that both Tshisekedi and Kagame will attend an emergency meeting on Wednesday to discuss the situation but the two leaders have not confirmed they will attend.

The lakeside city of Goma, on the border with Rwanda, is a vital transport and trading hub close to large sources of minerals that are essential in the manufacture of mobile phones among other things

Following a meeting on Tuesday, the African Union (AU) called on the M23 to lay down its arms.

The AU's peace and security commissioner, Bankole Adeoye, condemned the "violence by M23 and all other negative forces, and calls for full respect of DR Congo's sovereignty, unity and territorial integrity", a statement from the AU on X said.

As diplomats were discussing the situation, the rebels seemed to be gaining ground in Goma.

"They have taken control of the airport, M23 fighters are there," a security source told the AFP news agency.

"More than 1,200 Congolese soldiers have surrendered and are confined to the [UN base] at the airport."

Earlier on Tuesday, Adelheid Marschang, the World Health Organization's emergency response co-ordinator for the Democratic Republic of Congo spoke of "hundreds of people in hospital, most admitted with gunshot wounds".

Speaking to reporters in Geneva, the International Committee of the Red Cross (ICRC) said its hospital in Goma had received more than 100 wounded in just 24 hours, a number it previously received over the course of a month.

It said this had forced its staff to turn the hospital car park into a triage unit.

The use of heavy artillery in densely populated areas is causing severe injuries, particularly among children, it added.

In Kinshasa, angry crowds targeted the French, Kenyan and Ugandan embassies among others.

They stormed the streets, burning tyres and disrupting traffic.

Authorities in Kinshasa have since banned protests in the city. The US embassy told its citizens to leave the country "while commercial [flight] operations are available" following the attacks, while the European Union's foreign policy chief Kaja Kallas branded them "unacceptable" and "deeply troubling".

As well as civilian deaths, South Africa said on Tuesday that four more of its soldiers, who are in DR Congo as part of peacekeeping efforts, had died as a result of clashes with the M23.

This brings the total number of South African deaths to 13. Malawi and Uruguay have also lost peacekeepers.

South Africa's President Cyril Ramaphosa on Monday spoke to his Rwandan counterpart Paul Kagame, with the two agreeing on an urgent need for a ceasefire and resumption of peace talks.

The Congolese government has also asked for another meeting of the UN Security Council – demanding that this time it take tough action against Rwanda.

During an emergency UN meeting on Sunday, DR Congo demanded sanctions against Rwanda, saying its forces had crossed into its territory in what amounted to a "declaration of war".

Following the meeting, the UN condemned M23 advances and the "ongoing flagrant disregard for the sovereignty and territorial integrity of the DR Congo", including the presence of "external forces".

Rwanda has in the past denied direct support for the M23, but UN peacekeeping chief Jean-Pierre Lacroix has said there is no doubt its troops were supporting the rebels.

Additional reporting by Emery Makumeno in Kinshasa, Imogen Foulkes in Geneva and Basillioh Rukanga and Barbara Plett Usher in Nairobi.