But halting progress, ever-more deadly drone attacks and unmoving negotiating positions seem to have taken their toll. On Thursday, Trump used a striking analogy to concede the warfare was nowhere near over, and that he did not, at that moment, feel it was best to intervene.

Neither Russia nor Ukraine has a clear path to victory. The Ukrainian drone attack last week and the Russian air raids on Friday don't change that.

Asked about the comment, Kremlin spokesman Dmitry Peskov said: "Here, of course, the U.S. president may have his own point of view on what is happening, but for us this is an exis