U.S. Secretary of State John Kerry and Russian Foreign Minister Sergei Lavrov are due to hold talks on the Ukraine crisis in Paris on March 30.
Kerry was flying home from the Middle East on March 29 when he quickly changed plans and ordered the plane fly to France.
The scheduled meeting comes after President Barack Obama and President Vladimir Putin spoke by phone late on March 28.
During the call, Obama urged Russia to pull its troops back from Ukraine's eastern border.
On March 29, Lavrov told Russian TV that Moscow had no intention to send troops into Ukraine, but added Russia is ready to protect the rights of Russians and Russian-speaking people in Ukraine.
NATO Secretary General Anders Fogh Rasmussen, in an interview with Germany's Focus magazine published on March 29, said the alliance is "extremely worried."
Also on March, representatives of Crimea's Tatar minority condemned Russia's annexation of the peninsula and appealed to international bodies for recognition as an autonomous group.
Crimean Tatars' assembly leader Refat Chubarov addressed the more than 200 delegates in the Tatars historic capital of Bakhchiseray.
"We are talking about the rights of the Crimean Tatar people to self-determination -- possibly all the way to national and social autonomy. We are addressing the governments of all countries with no exception. We are especially addressing the governments of those countries, which have areas within their federations whose borders are determined by the rights of ethnic majorities living in them," Chubarov said.
Meanwhile, political parties in Ukraine have picked candidates to run in planned presidential elections on May 25.
In a major development, the former boxer and political leader Vitaly Klitschko announced he would not run for president but would instead back billionaire chocolate tycoon Petro Poroshenko as the candidate for the UDAR party.
Analysts say the move means the race will likely be a battle between Poroshenko and former prime minister Yulia Tymoshenko.
As expected, Tymoshenko's Batkyvshchina (Fatherland) Party nominated her to run as their presidential candidate in the upcoming election.
In her speech to a party congress on March 29, Tymoshenko lashed out at Russian President Vladimir Putin:
"[Russian President Vladimir] Putin wants to punish us, Ukrainians, for our quest for freedom, for our European choice, for our courage to fight. Our response in Crimea, I think, has not been adequate. If you elect me to and entrust me with the post of President of Ukraine I will not give up a single centimeter of Ukrainian land to the aggressor without a fight," Tymoshenko said.
Candidates have until April 4 to register as candidates for the vote, which will take place following Russia’s annexation of Crimea, deepening economic problems, and as the country's mainly Russian-speaking eastern regions are expressing growing discontent toward Kyiv.
Based on AP and Reuters reporting