The meeting follows US President Donald Trump's pledge during a White House summit on Monday to support security guarantees aimed at helping end Russia's war in Ukraine.
Trump has ruled out sending US troops into Ukraine but suggested Washington could provide some form of air support, the Reuters news agency reported.
US Air Force Gen. Alexus Grynkewich, who oversees NATO operations in Europe, is expected to brief the gathering on last week's meeting in Alaska between Trump and Russian President Vladimir Putin.
The British government said members of the so-called Coalition of the Willing, which met virtually on Tuesday, agreed that their planning teams would meet with US counterparts in the coming days to advance plans for Ukraine's security guarantees, Reuters reported.
Russia launched a full-scale invasion of Ukraine on February 24, 2022, starting the largest armed conflict in Europe since World War II.
Wednesday marks day 1,274 of the war.
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Source: Reuters, IAR, PAP