Ruto's appeal comes after the United Nations Mission in DRC reported that over 3,000 people so far have been killed in a fight between M23 militants and the national army over control of a key eastern city of Goma.
Vivian van de Perre, the deputy head of the United Nations mission in the DRC, told reporters that UN teams are "actively helping" the M23 to collect the dead from the city's streets.
According to her, by Wednesday 2,000 bodies had been retrieved and 900 others were in hospital morgues.
"We expect this number to go up," she said adding, "There are still many decomposing bodies in many areas. The World Health Organization is worried about what kind of epidemic outbreaks that can contribute to."
In early January, the M23 broke a ceasefire agreement, launching a large-scale offensive in the mineral-rich east with the support of the Rwandan army.
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On Jan 27, the M23 said it had captured Goma, the capital of North Kivu province and a city of more than a million people, thousands of whom have been displaced from other conflict areas.
But Ruto in his sentiments said the international community must stand in solidarity with the people of DRC "during this time" by aligning their support with the EAC-SADC initiative.
"We must resist the temptation of thinking that we can somehow shoot or bombard our way into a solution in the face of the complexity involved," he said.
The President made it clear that the only way to ensure enduring peace is to engage in a comprehensive diplomatic approach that addresses the root causes of the conflict, secures DRC's territorial integrity and affirms the sovereignty of its people, their aspirations for freedom, justice and development.
"Such an approach must also bring together multiple stakeholders - regional States, international and political organisations, civil society and the DRC government to dialogue and collaborate in exploring, developing and implementing a lasting solution," President Ruto said.
The President said the East African Community (EAC) and the Southern African Development Community (SADC) must stand together in calling for dialogue and a peaceful resolution to the conflict.
He said all parties should give priority to dialogue, cooperation and, above all, the protection of civilians.
He noted that dialogue is not a sign of weakness, but a "testament to our collective wisdom and strength as leaders and as a community".
President Ruto told the EAC and SADC leaders that they have a singular opportunity to build on the gains and lessons of the Luanda and Nairobi peace processes.
"We have a historic opportunity as the broader neighbourhood of the DRC to mobilise our collective will into a fused, single and coherent initiative towards the resolution of this complex crisis," he said.
President Ruto called on the summit to muster "total commitment" and facilitate a sustainable settlement that lays the foundation for a stable and prosperous DRC.
"Today, we join together to reiterate our calls to the parties to this tragic conflict to immediately cease hostilities and take positive actions to allow meaningful dialogue aimed at the restoration of stability," he said.
Ruto noted that there is also a clandestine international dimension at work whose persistent, cynical and destructive effects must neither be underestimated nor ignored any longer.
As a result, he said, it was clear that the conflict could not, therefore, be resolved through military means.
While imploring the M23 not to engage in retaliatory attacks, Ruto said an immediate ceasefire is the only way by which the region can create necessary conditions for constructive dialogue and implementation of a comprehensive peace agreement.
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"The security of the DRC is essential not only to the stability of the country but also to the prosperity and cohesion of the entire EAC and SADC," he said.
His SADC counterpart Emmerson Mnangagwa of Zimbabwe called for an end to the conflict.
Mnangagwa urged SADC and EAC leadership to unite and explore ways of addressing the conflict to avert further loss of lives and destruction of property.
"Unity and prosperity of the people of our continent should be our focus. We must remain united as we were in the fight against colonialism," he said.
He said it was crucial to approach the war in Eastern DRC with openness, honesty and flexibility if a lasting solution was to be realised.
"Dialogue among all parties is critical in this process. I am confident this summit will come up with a roadmap for restoring peace and stability in DRC," he said.