According to him, the number of prisoners is being specified; currently it is more than two dozen.
"[We held] crumpled talks. The issue of 200s, 300s (dead and wounded - ed.) is being addressed now. There is a need to deliver medicines and food," he said.
"We had contact (with the militants - ed.). We were promised that the prisoners will not be tortured, that they will have the status of prisoners of war and they will be given medical treatment," Ruban said, adding that some of the fighters are in Donetsk hospitals.
"Some of the men were given the opportunity to call and report that they are safe and in captivity," he added.
"The Donetsk inquiry agencies will conduct investigations, they will be questioned," Ruban said.
Answering the question whether there is a risk that some of the soldiers can be transferred to Russia, as had happened with Ukrainian pilot Nadiia Savchenko, he replied:
"The possibility exists, it may concern senior officers… Those who had some informational value were sent to the Russian Federation."
Responding to a question as to whether it is possible to agree that prisoners of war are not transferred to Russia, Ruban said:
"If the intelligence services of another state have an interest in any particular person, then it does not matter how you hold the negotiations.... Nadiia Savchenko is a good example. With all the assurances I received from the Luhansk party that she was ready for the exchange of prisoners, she was transferred to Russia based on the decision of the special services."
At the same time, Ruban said that the issue of exchange of imprisoned "cyborgs" is not on the agenda, since "the second part of the great exchange" is not complete yet.
"The lists are ready, the Donetsk side is ready, the delay is caused by the Ukrainian side. When the second part of this great exchange is finished, then will address the issue of exchanging the "cyborgs". There is a tank crew there and part of the 95th brigade battalion," he said.
Ruban also said that negotiations on prisoner exchange are hindered by the shelling of Donetsk.
"The negotiations on the 500s (POWs) are obstructed by the constant bombardment of Donetsk, with regular losses among civilians. So I have no arguments, nothing to retort. I say: "Let's show humanity." They say: "Let's do it. Stop shelling bus stops, kindergartens, where there were strikes yesterday, schools where there were strikes yesterday, and hospital where there were strikes yesterday. The shelling of houses hinders the negotiations regarding prisoners," he said.