Ukrainian Foreign Minister Dmytro Kuleba said there had not been any recent diplomatic communications between Russia and Ukraine at the level of their foreign ministries and that the situation in the port of Mariupol, which he described as "dire", may be a "red line" in the path of negotiations.
"Mariupol may be a red line", he told CBS News in an interview on Sunday.
Ukrainian soldiers resisted a Russian ultimatum to lay down arms on Sunday in the pulverized port of Mariupol, which Moscow said its forces had almost completely seized in what would be its biggest prize of the nearly two-month war.
