"Most likely, in July would be a Normandy Four telephone conversation at the level of leaders", Poroshenko said. And we do not rule out that we'll be able to arrange a summit following these phone talks.
During a short visit to Poland ahead of the G20 summit in Hamburg, Germany, this week - on the sidelines of which he met with Russian President Vladimir Putin for the first time - United States leader Donald Trump called on Russia to "cease its destabilizing activities in Ukraine and elsewhere".
According to the president, Ukraine is not interested in delaying such negotiations, because "Ukraine pays a high price - its heroes are wounded and killed" every day.
Ukraine's government has accused Moscow of supporting pro-Russian separatists in the Donbass, after Russia annexed Crimea from Ukraine in 2014.
Poroshenko, who said Volker would remain in Ukraine for the next several days, maintained that a resolution to the crisis "needs only the political will of Moscow".More news: Angelique Kerber through to face Garbine Muguruza in fourth round
Tillerson has appointed a special envoy to examine possibilities for jump-starting implementation of a two-year-old peace roadmap known as the Minsk Agreement.
The US and the European Union have imposed sanctions on Russian Federation, though Moscow has denied backing the rebels.
"Happy to welcome Secretary of state Rex Tillerson on his first official visit to Ukraine", - wrote Poroshenko in his microblog on Twitter on Sunday.
"The U.S. and European Union sanctions on Russian Federation will remain in place until Moscow reverses the actions that triggered these particular sanctions", the secretary of state said.
State secretary calls on Moscow to de-escalate Russia-backed conflict in east Ukraine, warning sanctions will remain.More news: Shia LaBeouf Somehow Got Arrested for Public Drunkenness in Savannah, Georgia
Poroshenko hailed U.S. involvement and reiterated Tillerson's commitment to seeking a negotiated peace deal.
"Most of all we want peace in Ukraine".
Mr Trump tweeted on Sunday that he had "strongly pressed" Mr Putin about Russian interference in the United States election and had discussed with him the possibility of creating "an impenetrable cyber security unit". "We firmly adhere to our commitments", Ukrainian leader said. During the meeting, Mr. Trump broached the subject of election interference, and Putin denied any role in hacking the 2016 election.
Tillerson told reporters Sunday that the U.S.is going to have a dialogue on how to gain such assurances from their Russian counterparts, adding "the important thing is how do we assure that this doesn't happen again".More news: Humid with more showers this afternoon