Rubio Warns U.S. May Withdraw from Ukraine Talks

US Secretary of State Marco Rubio warned on April 29 that unless Russia and Ukraine put forward specific plans for ending the war in Ukraine, the United States will curtail its efforts to mediate. State Department spokeswoman Tammy Bruce cited Rubio as saying that the time had been reached at which "concrete proposals need to be delivered by the two parties on how to end this conflict." If there is not progress, the United States “will step back as mediators in this process," Bruce told reporters. Later on April 29 at a UN Security Council…