In a televised exchange, President Vladimir Putin was shown asking his foreign minister, Sergei Lavrov, whether there was a chance of an agreement to address Russia's security concerns, or whether it was just being dragged into tortuous negotiations.
Lavrov replied: "We have already warned more than once that we will not allow endless negotiations on questions that demand a solution today."
But he added: "It seems to me that our possibilities are far from exhausted ... At this stage, I would suggest continuing and building them up."
Washington has said Russia could invade Ukraine "any day now", and British Prime Minister Boris Johnson on Monday called the situation "very, very dangerous".
Russia has positioned more than 100,000 troops near to Ukraine's borders but denies planning to invade, accusing the West of hysteria.
Earlier in the day, the Group of Seven large Western economies (G7) had warned Russia of "massive" economic consequences if it did invade, and promised Kyiv swift support.
Ukraine's ambassador to Britain backtracked on remarks suggesting that Kyiv would reconsider its attempt to join NATO - one of Russia's primary concerns - but did say that other concessions could be on offer.
"We are not a member of NATO right now and to avoid war we are ready for many concessions and that is what we are doing in conversations with the Russians," he told the BBC in a clarification.
"It has nothing to do with NATO, which (membership application) is enshrined in the constitution."
The Kremlin said that if Ukraine renounced its aspiration to join the Western military alliance, it would significantly help address Russia's concerns.
Moscow has made clear it sees the former Soviet republic's quest for closer ties with the West, notably through NATO, as a threat.
Lavrov told Putin the United States had put forward concrete proposals on reducing military risks, but that responses from NATO and the European Union - which has been at pains not to let Moscow divide its members - had not been satisfactory.
None of my fellow ministers responded to my direct message," Lavrov said. "Therefore we will continue to seek a concrete response from each country."
An EU official, who asked not to be named but has spoken to Putin by phone in the past, said US talks with Russia were yielding little.
"Russia is trying to demonstrate that it is the policeman in the region," the source said. "The criticism by Moscow against Ukraine is this idea that the people made a choice for liberal democracy, values, principles and freedoms."
German Chancellor Olaf Scholz held talks in Kyiv with President Volodymyr Zelenskiy, to be followed on Tuesday by a meeting with Putin in Moscow.
He told reporters he saw "no reasonable justification" for Russia's military activity on Ukraine's border, and that Russia should accept offers to discuss European security.Â
While Zelenskiy affirmed that Ukraine still wanted to join NATO, Scholz said it was strange that Russia had raised the issue now, when it was "not on the agenda".
Kyiv has long resented the German-Russian Nord Stream 2 project - a pipeline that will allow Russia to circumvent Ukraine in exporting gas to Germany - and has bristled at Germany's refusal to join other NATO partners in selling it weapons.
Germany did, however, begin sending troops on Monday to help NATO member Lithuania bolster NATO's border with Russia.
