BRUSSELS — The confrontation between Russia and the United States over Ukraine deepened on Wednesday, as leaked documents confirmed the U.S. and NATO rejection of key Russian security demands, while the Biden administration ordered 3,000 additional troops into Eastern Europe.
Although the leaked documents showed the United States had offered to provide more transparency about missile deployments in Eastern Europe, the basic message to Moscow was American and NATO resolve not to bow to Russian demands, in a dispute that has pushed relations to their worst since the Soviet era.
The broad outlines of the U.S. and NATO written replies to the Kremlin had already been known — and President Vladimir V. Putin of Russia said Tuesday that Moscow’s demands had basically been ignored, even as he said his government was still analyzing the responses.
But the publication of those answers provided additional detail and reinforced the obstacles to a resolution, as fears escalated in the West about the large Russian troop buildup surrounding Ukraine.
Even as diplomacy aimed at defusing the crisis intensified on Wednesday, the responses, delivered to the Kremlin last week, underscored the pressure on Mr. Putin to decide whether to go to war over demands the West has rejected or to take up the opportunity to negotiate arms control agreements offered by the West. He said on Tuesday that the United States was trying to goad Russia into war.
The American and NATO replies to Russia were obtained and published by El País, the Spanish daily, and confirmed by John F. Kirby, the Pentagon press secretary.
“I note that in the past few hours a proposal made by the United States leaked to a European news outlet,” Mr. Kirby said. “We did not make this document public, but now that it is, it confirms to the entire world what we’ve been saying.”
President Biden’s new troop deployment order appeared aimed at reinforcing the message that the United States and its 29 NATO partners were unified in their resolve, and at reassuring NATO members closer to the Russian border.
The troops, including 1,000 already in Germany, will head to NATO members Poland and Romania, Mr. Kirby, said, though there remains no intention of sending troops into Ukraine. He said the deployment was meant to be temporary.
“We are making it clear that we are going to be prepared to defend our NATO allies if it comes to that,” Mr. Kirby said.
Jen Psaki, the White House press secretary, said in explaining the deployment that there was “no question that Russia and President Putin has continued to take escalatory, not de-escalatory steps.”
The initial response from Moscow was negative. “The unfounded destructive steps will only fuel military tensions and narrow the field for political decisions,” Aleksandr V. Grushko, a deputy foreign minister, was quoted as saying by the Interfax news agency.
The developments came as top European leaders pushed a diplomatic outreach to Mr. Putin. Prime Minister Boris Johnson of Britain spoke with him by phone, and Mr. Johnson’s office said they had agreed on the need for a “peaceful resolution” and that “aggravation was in no one’s interest.”
President Emmanuel Macron of France, who has spoken with Mr. Putin at least twice in the past week, spoke with Mr. Biden later Wednesday. In a readout of their phone call, the French presidency said the two leaders had shared the same “logic of de-escalation.” Mr. Macron is scheduled to talk with the leaders of Russia, Ukraine and Poland on Thursday.
Olaf Scholz, Germany’s new chancellor, told the German broadcaster ZDF that he planned to meet with Mr. Putin soon but did not specify a date.
Moscow issued its security demands in mid-December, as the West sounded alarms about a potential invasion of Ukraine. Among the most contentious were Russia’s insistence that Ukraine, a former Soviet republic of 44 million, never be allowed to join NATO, and that the West scale back its military presence in Eastern Europe to mid-1990s levels.
Mr. Putin wants to expand Moscow’s sphere of influence to something resembling the one it had before the Soviet Union’s collapse 30 years ago. He has described the possibility of Ukraine joining NATO as a threat not just to Russia, but to world peace.
If Ukraine were to align itself fully with the West and acquire NATO weapons, he suggested on Tuesday, it might go to war to recapture Crimea — which Russia seized in 2014, a move unrecognized by the international community. That, he said, could lead to war between Russia and the NATO bloc.
Mr. Putin, whose renewed troop buildup along Ukraine’s borders led to the current crisis, has regularly expressed concern that NATO’s Aegis missile-defense systems in Romania and Poland could also fire offensive Tomahawk cruise missiles at Russia. NATO and Washington insist that the systems are only defensive and are not aimed not at Russia but at other possible adversaries, like Iran.
In its response, the Biden administration proposes a reciprocal “transparency mechanism” under which Russia could verify the absence of offensive missiles at the sites in Romania and Poland, while the United States would do the same at two missile-launching bases of its choice in Russian territory; one would likely be in Kaliningrad, the slice of Russia bordering two NATO members, Lithuania and Poland.
Moscow has stationed intermediate-range missiles in Kaliningrad that can carry conventional and nuclear warheads, one reason the United States and its allies abandoned the 1987 Intermediate-Range Nuclear Forces Treaty, known as the I.N.F. Treaty, in 2019.
Ukraine’s foreign minister, Dmytro Kuleba, endorsed on Wednesday another U.S. proposal to help defuse the crisis: an assurance that it would not deploy offensive missiles or permanently base ground troops in Ukraine. The proposal was presented to Russia as contingent on consultations with the Ukrainian government.
The United States and its NATO allies say they have no combat troops or missiles in Ukraine, and no intention of deploying offensive military capabilities there. They have also made clear that they would not wage war against Russia to defend Ukraine, which is not covered by NATO’s commitment to collective defense.
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NATO promised in 2008 that Ukraine and Georgia could one day join the alliance, though it appears no closer to happening now than it did then. The pledge infuriated Mr. Putin, who was already incensed that NATO had added the former Soviet Baltic republics and former Soviet satellites like Poland.
The Russian president has been trying ever since to ensure NATO’s door remains shut, including to Finland and Sweden.
The offer to rule out future U.S. deployments in Ukraine addressed a concern Mr. Putin has raised repeatedly: that if Ukraine were to join the alliance, missiles deployed there could reach Moscow in mere minutes.
But it was not a clear-cut concession to Russia. The proposal called for reciprocal commitments by both Russia and the United States to refrain from deploying missiles or troops in Ukraine. Not only has Russia annexed Crimea, it also backs a separatist insurgency that holds a slice of eastern Ukraine.
“I would like to note that while the United States has neither missiles nor combat units in Ukraine, Russia has both,” Mr. Kuleba said in a video call with foreign journalists. “And if this proposal is accepted on a reciprocal basis, that will imply that Russia has to withdraw. So, no, we have no objections.”
Mr. Kuleba said he remained hopeful, in part simply because the diplomacy was continuing despite warnings from Western governments, starting months ago, that an intervention could begin in December or January, and “now we are at the beginning of February.”
In the leaked documents, the United States also proposed negotiations with Moscow on other arms-control measures, announced publicly in Washington in the past. They include a treaty to replace the current New START accord limiting intercontinental-range missiles, and talks to enhance transparency on military exercises and reduce the risk of accidental conflict.
The United States is also prepared to discuss another Russian concern, known as the “indivisibility of security” — the idea that a nation may not seek to increase its security at the expense of another’s.
But Washington rejected any restraint on the rights of any sovereign country “to choose or change its security arrangements, including treaties of alliance.”
Both Washington and NATO also rejected the Russian demand that they negotiate separate treaties with Moscow that would require them to remove all troops and equipment from NATO member countries that border Russia, including Poland and the Baltic States.
Washington insisted that NATO’s enhanced forward battalions in Poland and the Baltic countries, established after Russia annexed Crimea and supported separatists in eastern Ukraine, were not “permanent,” since they rotate. It said those deployments, totaling 5,000 troops, did not constitute “substantial combat forces,” in accordance with a 1997 agreement between NATO and Russia.
Instead, the documents say that any more Russian buildup or aggression aimed at Ukraine “will force the United States and our Allies to strengthen our defensive posture.”
The documents that the United States and NATO provided to Moscow are relatively general in tone and do not attempt to draft treaty language. Instead, they set out for Russia where the United States and NATO are prepared to engage in negotiations once Russia de-escalates around Ukraine.
El País did not describe how it obtained the documents; the Kremlin spokesman, Dmitri S. Peskov, said on Wednesday that Russian authorities had not released them.
Steven Erlanger reported from Brussels and Andrew E. Kramer from Kyiv, Ukraine. Michael Crowley, Helene Cooper, Eric Schmitt and Zolan Kanno-Youngs contributed reporting from Washington, Roger Cohen from Paris, Shashank Bengali and Marc Santora from London, and Rick Gladstone from New York.