Russia said it was clear the United States was not willing to address its main security concerns in their standoff over Ukraine, but kept the door open for further dialogue.
The United States and NATO submitted a written response on Wednesday to demands Russia has made for a redrawing of post-Cold War security arrangements in Europe since it massed troops near Ukraine, prompting Western fears of an invasion.
Kremlin spokesman Dmitry Peskov said Moscow needed time to review the response and would not rush to conclusions, but that US and NATO statements describing Russia's main demands as unacceptable did not leave much room for optimism.
"Based on what our (US and NATO) colleagues said yesterday, it's absolutely clear that on the main categories outlined in those draft documents ... we cannot say that our thoughts have been taken into account or that a willingness has been shown to take our concerns into account," he said. "But we won't rush with our assessments."
The nuanced Kremlin reaction made clear that Russia was not rejecting the US and NATO responses out of hand or closing the door to diplomacy.
US Under Secretary of State for Political Affairs Victoria Nuland on Thursday said the United States hoped Russia would study what Washington had offered and come back to the table.
"We are unified, unified in our preference for diplomacy. But we are also unified in our resolve that if Moscow rejects our offer of dialogue, the costs must be swift and severe," Ms Nuland told reporters.
The Russian foreign ministry said the best way to reduce tensions was for NATO to withdraw forces from eastern Europe, but also sought to quash fears of an invasion.
"We have already repeatedly stated that our country does not intend to attack anyone. We consider even the thought of a war between our people to be unacceptable," said Alexei Zaitsev, a ministry spokesman.
Sovereign dollar bonds issued by Ukraine soared on Thursday, enjoying their best day in almost two years, while Russian debt also gained after the Kremlin's response.
But, in a sign of lingering international concern, oil hit seven-year highs above $US90 ($A128) a barrel, then eased later. Russia is the world's second-largest oil producer and the crisis over Ukraine has fanned fears that energy supplies to Europe will be disrupted.
A Ukrainian presidential adviser told Reuters that Kyiv wants to borrow some $US5 billion ($A7.1 billion) from international organisations and in bilateral aid as borderline "hysteria" over the threat of a Russian attack was limiting its access to capital markets.
Russia has boosted its troop numbers by 15 per cent. Source: AP
Diplomatic window
Ukrainian President Volodymyr Zelenskiy will speak by phone later on Thursday with US President Joe Biden on issues of security, energy and macro-financial support, Mr Zelenskiy's spokesman said.
Russia's security demands, presented in December, include an end to further NATO enlargement, barring Ukraine from ever joining and pulling back the alliance's forces and weaponry from eastern European countries that joined after the Cold War.
The US and NATO responses were not made public, but both had already rejected those demands while expressing willingness to engage on issues such as arms control, confidence-building measures and limits on the size and scope of military exercises.
Turkey, a NATO member that has good ties with both Kyiv and Moscow, said it was important to keep talking. "All problems cannot be solved with a document, one or two meetings," Turkish Foreign Minister Mevlut Cavusoglu said in Ankara.
China told the United States it wants all sides involved in Ukraine to remain calm.
"We call on all parties to stay calm and refrain from doing things that agitate tensions and hype up the crisis," China's Foreign Ministry quoted Foreign Minister Wang Yi as telling US Secretary of State Antony Blinken in a telephone call.
Western countries have warned of economic sanctions on Russia if it invades Ukraine, building on measures imposed since 2014, when Moscow annexed Crimea and Russian-backed separatists began fighting the Kyiv government's forces in eastern Ukraine.
Ukrainian, Russian, German and French diplomats discussed the conflict in eastern Ukraine in Paris on Wednesday and agreed more talks should be held in Berlin in two weeks.
Ukraine's Foreign Minister Dmytro Kuleba said the agreement on more talks meant Russia was likely to remain on a diplomatic track for at least two weeks.
Russian Foreign Minister Sergei Lavrov said there was hope of starting serious dialogue with the United States, but only on secondary questions, not on fundamental ones. In comments published on his ministry's website, he said President Vladimir Putin would decide Russia's next move.
Mr Putin, who has not spoken publicly on the crisis for weeks, has warned of an unspecified "military-technical response" - something defence analysts say could relate to missile deployments - if Russia's demands are ignored.
