Russia cannot comment on Donald Trump's idea for ending the war in Ukraine because Moscow does not know what it involves, a Kremlin spokesman says.
Trump said during his debate against President Joe Biden if he won the November US election, he would have the war settled before he took office in January.
"This is not Trump's first statement on this, and he has made statements along these lines before. Without knowing the essence of what this is about, we cannot comment on it," Kremlin spokesman Dmitry Peskov told reporters.
The Kremlin has said any peace plan for Ukraine proposed by a possible future Trump administration would have to reflect the reality on the ground, where its forces control nearly a fifth of Ukraine, but Russian President Vladimir Putin was open to talks.
Ukraine says Russia's terms for ending the war amount to a demand for its surrender.
Trump has not said how he would go about ending the war, now well into its third year.
In Thursday's debate, he said Russia would not have invaded Ukraine in February 2022 if there had been a "real president" in the US who was respected by Putin.
Biden said Trump had "no idea what the hell he's talking about".
The Kremlin's comments came as Hungarian Prime Minister Viktor Orban, an outspoken critic of Western military aid to Ukraine, paid a surprise visit to Kyiv for talks with President Volodymyr Zelenskiy.
Orban, who has the warmest relations of any European leader with Putin, arrived a day after Hungary assumed the rotating six-month presidency of the EU Council. It is his first visit to Kyiv in more than a decade.
"The aim of the Hungarian presidency is to contribute to solving the challenges ahead of the European Union. That's why my first trip was to Kyiv," Orban wrote on Facebook under a photograph of him shaking hands with Zelenskiy.
Separately, his press chief Bertalan Havasi told Reuters in an email the two leaders would discuss bilateral relations, saying "the most important topic of the talks is the chance to create peace", but gave no details.
Zelenskiy and Orban were expected to deliver statements to reporters later on Tuesday.
Ties between the neighbours have come under heavy strain since Russia launched its full-scale invasion of Ukraine, with Budapest often opposing EU efforts to support Kyiv.
Under Orban, who upset Western partners by holding talks with Putin in October, Hungary has repeatedly accused Ukraine of curbing the rights of roughly 150,000 ethnic Hungarians living in the far west of Ukraine.
Kyiv has denied any such infringements but said it will do everything to address Budapest's concerns, which centre around the ethnic Hungarian minority's language rights and native-language schooling.
Ukraine is keen to secure Hungary's backing as it relies heavily on financial and military support from the 27-member EU, where unanimity is needed for many decisions.
