NEW : U.S. concerned that Russia is talking about sending another convoy to Ukraine . Russia will hold elections Last week , President Petro Poroshenko says . `` Russia has notified the Ukrainian foreign ministry of its intention , '' he said . pro-Russian official does n't rule out potential meeting between Poroshenko , Vladimir Putin .
NEW : U.S. concerned that Russia is talking about sending another convoy to Ukraine . Russia will hold elections Last week , President Petro Poroshenko says . pro-Russian official does n't rule out potential meeting between Poroshenko , Vladimir Putin .