US Army Secretary Dan Driscoll is meeting with a Russian delegation in Abu Dhabi on Tuesday, US and British media reported, days after talks with Ukraine in Geneva aimed at ending the conflict.
Driscoll met the Russian delegation on Monday with talks due to continue on Tuesday, ABC News and the Financial Times reported, citing a US official.
The latest talks were previously undisclosed, and follow meetings held in Switzerland between US and Ukrainian officials aimed at resolving the war with Russia.
The Financial Times said the head of Ukrainian military intelligence Kyrylo Budanov would be present at the talks, without detailing the Russian officials.
"Driscoll has been involved with this peace process pretty hot and heavy in the past few days," a US official told the Financial Times, without being named.
"Obviously, Ukraine knows what's going on, they knew where he was coming" after Geneva, he added, according to the paper.
Kremlin spokesman Dmitry Peskov neither confirmed nor denied the meetings.
"I have nothing to say. We are following the media reports," he told Russian state media.
The United States has been pushing Ukraine to accept its proposals to end the war, despite Kyiv saying the plan concedes too much to Moscow.
The US plan, originally made up of 28 points, would see Ukraine effectively cede its eastern Donetsk and Lugansk regions to Russia and slash the size of its military - demands that Kyiv has described as unacceptable.
Ukrainian, US and European officials met in Geneva on Sunday to draft an "updated" version of the plan, but the Kremlin responded on Monday that it would not accept European amendments.
Russia launched its full-scale invasion of Ukraine in February 2022.
Kyiv and its European allies say the war, the largest and deadliest on European soil since World War II, is an unprovoked and illegal land grab that has resulted in a tidal wave of violence and destruction.
Tens of thousands of civilians and military personnel have been killed since the invasion began, while millions of Ukrainians have been forced to leave their homes.
(AFP)