Mr Ruto had in the morning announced that he had spoken to Tshisekedi and his Rwandan counterpart Paul Kagame and that both had given their word they would attend.
Kenyan President William Ruto on Monday evening disclosed that he had spoken to French President Emmanuel Macron regarding the escalating crisis in Eastern Democratic Republic of Congo.
According to President Ruto, Mr Macron expressed support for regional efforts to address the turmoil, particularly as M23 rebels seized control of Goma, the capital of North Kivu Province, earlier that morning.
The rebel group's takeover sent shockwaves through the region, with reports of Congolese forces firing missiles into Rwanda. Rwanda Defence Forces claimed the shelling killed at least five civilians and left many injured, further straining relations between the two nations.
Despite President Ruto's announcement of an extraordinary East African Community (EAC) heads of state summit within 48 hours, Congolese President Félix Tshisekedi declined to attend.
Tina Salama, spokesperson for the Congolese presidency, cited security concerns as the reason for the snub.
"It is clear that, given the situation that prevails at the moment, the president will not be able to go to this summit," Ms Salama told local media.
She added that President Tshisekedi preferred the Luanda peace talks and African Union (AU) mediation, casting doubt on the EAC's ability to manage the crisis.
Earlier, President Ruto had stated that he had spoken to both President Tshisekedi and Rwandan President Paul Kagame, with assurances from both leaders that they would attend the summit. However, the absence of the Congolese leader leaves the regional bloc's intervention efforts in question.
Sign up for free AllAfrica Newsletters
Get the latest in African news delivered straight to your inbox
Meanwhile, Ugandan President Museveni held separate meetings in Kampala with UK High Commissioner Lisa Chesney and US Ambassador William Popp.
The discussions are believed to have centred on the growing instability in the Eastern DR Congo.
The crisis deepened as M23 rebels celebrated their victory in Goma, parading with civilians on the streets. While the group claimed to have restored calm in the city, the situation remains highly volatile across the region.
In a move diverging from the often-touted slogan "African problems must be solved by Africans," President Ruto's engagement with President Macron drew mixed reactions. West African nations like Burkina Faso and Mali have recently expelled France from their affairs, heightening criticism of foreign involvement in Africa.
Nevertheless, President Ruto announced that President Macron had pledged support for regional interventions in Eastern DR Congo, as well as Kenya's participation in peace initiatives in Somalia, Sudan, and South Sudan.
With EAC's unity under strain and tensions escalating, the international community is closely monitoring how the crisis will unfold in the coming days.
