U.S. official: Talks with Ukraine were productive, but major differences remain

After meeting with Ukrainian and European figures in London for several hours, Kellogg, the U.S. government's special envoy for Ukraine, said he thought the current round of talks on Ukraine was "candid, positive and productive." But another senior U.S. official said there were still major differences between the two sides on the U.S.-proposed framework and timetable for ending the conflict.