KYIV, May 4 - U.S. Secretary of State Antony Blinken is due in Ukraine on Wednesday in a show of support after Russia last month amassed and then pulled back its troops from border regions and Crimea, RFE/RL reported.

Blinken’s visit is a show of "unwavering" U.S. support for Ukraine's "sovereignty and territorial integrity in the face of Russia's ongoing aggression," State Department spokesman Ned Price said in a statement.

Russia military buildup near Ukraine's northern and eastern borders as well as in Crimea, which Moscow seized in 2014, raised concerns in Kyiv, Brussels, and Washington about a major escalation.

Moscow announced on April 23 that it had started withdrawing its forces, bringing at least momentary relief in Kyiv. The Russian military said last week that most of its troops had returned to their permanent bases.

Philip Reeker, the top U.S. diplomat for Europe, told reporters in a briefing last week that the United States will continue to monitor the situation.

"We have made very clear in our engagement with the Russian government that they should refrain from escalatory actions and cease aggressive activity in and around Ukraine," Reeker said, who also noted Washington’s concern about Russian exercises in the Black Sea.

Blinken will meet President Volodymyr Zelenskiy and also push for action against corruption, a longstanding demand of Ukraine’s Western partners, Price said.

Concerns about corruption, notably in Ukraine's energy sector, resurfaced this week over the government's replacement of the board of Ukraine's state-owned oil and gas company Naftogaz.

Price said the move to oust well-regarded experts “reflects a disregard for fair and transparent corporate governance practices and complicates long-standing efforts to reform Ukraine’s energy sector and improve its investment climate.”

The government on April 28 announced the dismissal of Andriy Kobolyev, Naftogaz’s chief since 2014, citing the "unsatisfactory" results of the company’s operations last year, when it posted a loss of nearly $700 million.

The supervisory board, which was temporarily suspended in order to dismiss Kobolyev, issued a statement on April 30 saying that all its members were submitting notice of their resignations, effective from May 14.

Blinken will arrive in Kyiv from London, where he attended a meeting of foreign ministers of the Group of Seven (G7) industrialized democracies.

His trip comes as President Joe Biden ramps up pressure on Russia but also prepares for a proposed summit with President Vladimir Putin in hopes of stabilizing the relationship. (rfe/ez)