Russia's new ambassador to Ukraine arrived in Kiev on Monday, ending the half-year absence of a senior Kremlin diplomat to the former Soviet republic, DPA reported.
Mikhail Zubarov, a former high-level Russian government adviser for trade and economic policy, landed at Boryspil airport at 11 am (0900 GMT), the Interfax news agency reported.
"It is a great honour and responsibility to represent Russia in Ukraine. The Russian Federation is confident that Russo-Ukrainian relations have a great deal of potential," Zubarov said in a statement.
Russia's named Zubarov for the sensitive post in August, but Moscow delayed his posting, citing poor relations between Kiev and the Kremlin.
Russia's former prime minister Viktor Chernomyrdin had served as ambassador to Ukraine until June 2009, leaving Moscow without a senior diplomat in Kiev for seven months.
During his eight-year stay in Kiev, Chernomyrdin refrained from speaking in public in Ukrainian - a decision angering some Ukrainian nationalists sensitive to Moscow's former control of the country.
Zubarov's statement was made in Ukrainian on Monday.
Russia and Ukraine have long been divided over a host of issues, including natural gas pricing and shipments, trade barriers, Ukraine's possible plans for accession to the North Atlantic Treaty Organization, and Russian military forces based in Ukraine's Crimea region.
The top two candidates in Ukraine's ongoing presidential contest, former prime minister Viktor Yanukovych and Prime Minister Yulia Tymoshenko, have both criticized President Viktor Yushchenko for worsening relations with Russia in recent years.
The incumbent Yushchenko, a frequent critic of the Kremlin and in office since 2004, failed to obtain sufficient support in an initial round of voting on January 17.
Yanukovych and Tymoshenko have called for less confrontation between Kiev and Moscow.