KIEV, June 21 - President Petro Poroshenko said after meetings in Washington that Ukraine and the United States would soon sign a number of agreements boosting defense cooperation, Interfax Ukraine news agency reported on Wednesday.

Poroshenko said U.S. Defense Secretary Jim Mattis and Vice President Mike Pence had told him that key members of President Donald Trump's administration would visit Kiev in the next two to three months, according to Reuters.

"And very important agreements will be signed, including agreements on defense cooperation, including an agreement on defense procurement and an agreement on military-technical cooperation," Poroshenko was quoted as saying at a briefing.

Dmitry Peskov, Russian President Vladimir Putin’s spokesman, expressed some concerns over increasing cooperation between Ukraine and the U.S. in the defense sector.

Peskov again denied reports of the presence of Russian military forces in eastern parts of Ukraine despite mounting evidence and many Russian citizens captured by Ukrainian forces in the area.

"We hope that Washington (while deciding on supplies of lethal arms to Kiev) won’t forget that Ukraine is a country where civil war is continuing," TASS, Russia’s state news agency reported, citing Peskov.

U.S. President Donald Trump met with Poroshenko on Tuesday and expressed support for a peaceful resolution to the conflict in eastern Ukraine.

Poroshenko had a separate session with U.S. Vice President Mike Pence.

In a statement issued after Trump's meeting, the White House said the discussion centered on "support for the peaceful resolution to the conflict in eastern Ukraine and President Poroshenko's reform agenda and anti-corruption efforts."

A separate White House statement issued after Pence met with Poroshenko said the vice president highlighted continuing U.S. support for implementing the Minsk agreement, the 2015 accord aimed at ending Russian support for separatist rebels in eastern Ukraine. Last week, Secretary of State Rex Tillerson said the United States could back away from that agreement to avoid being "handcuffed" by the policy. Trump did not mention the accord. (rt/nr/ez)