In what was reportedly called a “drop-in” visit by the White House, Ukraine’s President Petro Poroshenko met President Donald Trump and Vice President Mike Pence at the Oval Office on Tuesday. Poroshenko praised Trump for his leadership during the visit which came on the same day as the Treasury Department imposed sanctions on 38 Russian individuals and organizations over Moscow’s activities in Crimea.

Ahead of his visit, Poroshenko’s office tweeted: "It is important that President of Ukraine will meet with President of the U.S. earlier than Putin." Trump is due to meet Russian President Vladimir Putin on the sidelines of the G20 summit in Hamburg, Germany, in July.

In a statement released by the White House after the two leaders met, Poroshenko was quoted as saying: “We're really fighting to bring freedom and democracy with your very strong support in security and defense — support of our defense, support of my 45 million nation, of the country who is the biggest in the European continent. And I'm absolutely confident that Ukraine is a story of success. I'm proud to have you, Mr. President, and United States as a co-sponsor to this story of success."

“And we very much admire of your leadership, of your very effective steps, because today includes two historic days – five months of your presidency and – when we launched the first peace plan – peace plan of Ukraine. And I'm absolutely confident that our effective coordination will bring the peace to our nation, to our land, and can support our territorial integrity and sovereignty," he asserted.

Read: Two Years After Crimea Annexation, Region Is A ‘Black Hole’ For Human Rights

During the meeting, Pence highlighted U.S. support for the peaceful resolution of the conflict in eastern Ukraine, and Normandy format negotiations to implement the Minsk agreements, another White House press statement said. The vice president “stressed the importance of continued reforms to fight corruption, improve the business climate, and keep Ukraine's International Monetary Fund program on track," the statement said.

Poroshenko also met with Secretary of State Rex Tillerson and Secretary of Defense James Mattis. On June 14, Tillerson said the U.S. could not back away from the Minsk agreement. "I think it is important that we be given sufficient flexibility to achieve the Minsk objectives. It is very possible that the government of Ukraine and the government of Russia could come to a satisfactory resolution through some structure other than Minsk," Reuters reported.

Photo: Reuters

The Minsk peace agreement was signed by Russia and Ukraine in February 2015 to give eastern Ukraine more autonomy. The agreement, brokered by France and Germany, called for a ceasefire, withdrawal of heavy weapons from the front line and constitutional reform in eastern Ukraine, the report said.

Trump met his Ukrainian counterpart shortly after the Treasury Department imposed sanctions on 38 Russian organizations and individuals “to seek a diplomatic resolution to the crisis in Ukraine and to facilitate Crimea’s return to Ukraine," according to the official statement.

Read: Moscow Launches Land, Air And Sea Drills Simultaneously In Crimea For First Time

“In today’s action, OFAC designated 38 individuals and entities under Ukraine-related authorities, including one entity that has engaged in the evasion of existing sanctions, two Russian government officials and two individuals acting for or on behalf of a government official, two entities that are owned or controlled by an individual previously designated, and 11 individuals and entities that operate in the Crimea region of Ukraine,” read the statement.

Poroshenko's office, on the official website, said U.S. will prolong the validity of sanctions against Russia. "The validity of the U.S. sanctions against Russia will be prolonged. It was stated by President Petro Poroshenko in the course of the briefing following the meeting with U.S. President Donald Trump within the working visit to this country answering the question whether the Head of State had received a clear confirmation from the U.S. President that sanctions against Russia would not be lifted until the return of Crimea and termination of Russian aggression against Ukraine," according to the statement published on the official website.

The sanctions come a week after Senate leaders in the U.S. passed a bipartisan deal to stop Trump from easing sanctions on Russia. However, according to Reuters, Trump said nothing about Russia during the meet with Poroshenko. The president described it as an honor to welcome Poroshenko at White House in a post tweeted from his official account.

The meeting is likely to complicate U.S.-Russia relations at a time when FBI has intensified investigations into Russian meddling in the 2016 presidential election.