State Department spokeswoman Victoria Nuland was asked by a reporter during a press conference on Thursday if Secretary of State John Kerry has heard from back from Russian Foreign Minister Sergei Lavrov after several days attempting to reach him.
Ms. Nuland confirmed that there has been no response from the Russians.
"So that's three days now," the reporter said. "Do they have any explanation why Mr. Lavrov is unavailable to the Secretary of State for three days? ... Do they have some sort of excuse?"
Mr. Lavrov's dismissals of Mr. Kerry's calls prompted another reporter on Wednesday to joke, "Maybe you could text him."
Mr. Kerry wants to talk to Russia about North Korea's recent nuclear tests, and has already spoken with the other members of the now-defunct six-party alliance that was attempting to find a diplomatic solution to the impasse, The Washington Times reported.