WASHINGTON--The United States and NATO on Friday roundly rejected Russian demands that the alliance not admit new members amid growing concerns that Russia may invade Ukraine, which aspires to join the alliance.

Secretary of State Antony Blinken and NATO Secretary General Jens Stoltenberg said Russia would have no say over who should be allowed to join the bloc. And, they warned Russia of a “forceful” response to any further military intervention in Ukraine.

Their comments amounted to a complete dismissal of a key part of Russian President Vladimir Putin’s demands for easing tensions with Ukraine. Putin wants NATO to halt membership plans for all countries, including Ukraine. The former Soviet republic is unlikely to join the alliance in the foreseeable future, but NATO nations won't rule it out.

Blinken and Stoltenberg spoke separately following an extraordinary virtual meeting of NATO foreign ministers. The meeting of the North Atlantic Council was the first in a series of high-level talks over the next week aimed at easing the tensions.

“We’re prepared to respond forcefully to further Russian aggression, but a diplomatic solution is still possible and preferable if Russia chooses," Blinken told reporters in Washington. He categorically dismissed Russia's claim that NATO had pledged not to expand eastward following the admission of several former Soviet satellites after the end of the Cold War.

“NATO never promised not to admit new members; it could not and would not,” Blinken said, accusing Putin of raising a strawman argument to distract from Russian military moves along the Ukrainian border.

“They want to draw us into a debate about NATO rather than focus on the matter at hand, which is their aggression toward Ukraine. We won’t be diverted from that issue,” Blinken said,

Earlier in Brussels, Stoltenberg made similar remarks as the allies prepared for the flurry of diplomatic contacts that will begin between the U.S. and Russia in Geneva on Monday and move to a NATO-Russia Council meeting and a pan-European meeting with Russia on Wednesday and Thursday.

“We will not compromise on core principles, including the right for every nation to decide its own path, including what kind of security arrangements it wants to be a part of,” Stoltenberg said.

The NATO-Russia Council meeting will be the first in more than two years and will give NATO ambassadors the chance to discuss Putin’s security proposals with Russia’s envoy face to face.

Much contained in documents Moscow has made public — a draft agreement with NATO countries and the offer of a treaty between Russia and the United States — appears to be a non-starter at the 30-country military organization, despite fears that Putin might order an invasion of Ukraine.

NATO would have to agree to halt all membership plans, not just with Ukraine, and to end military exercises close to Russia’s borders. In exchange, Russia would respect the international commitments it’s signed up to on limiting wargames, as well as end aircraft buzzing incidents and other low-level hostilities.

Endorsing such an agreement would require NATO to reject a key part of its founding treaty. Under Article 10 of the 1949 Washington Treaty, the organization can invite in any willing European country that can contribute to security in the North Atlantic area, as well as fulfill the obligations of membership.

Blinken said Moscow was well aware that NATO would not accept the demands.

“Certainly part of (Putin's) playbook is to put out a list of absolutely non-starter demands and then to claim that the other side is not engaging and then use that as somehow justification for aggressive action," Blinken said.

Stoltenberg said the Russian military buildup that sparked the invasion worries has continued.

"We see armored units, we see artillery, we see combat-ready troops, we see electronic warfare equipment and we see a lot of different military capabilities,” he said.

This buildup, combined with Russia's security demands, and its track record in Ukraine and Georgia, "sends a message that there is a real risk for a new armed conflict in Europe,” Stoltenberg said.

Russia annexed Ukraine’s Crimean Peninsula in 2014 and later backed a separatist rebellion in the country’s east. Over more than seven years, the fighting has killed over 14,000 people and devastated Ukraine’s industrial heartland, known as Donbas.

Russia denies that it has fresh plans to attack its neighbor, but Putin wants legal guarantees that would rule out NATO expansion and weapons deployments. Moscow says it expects answers to its security proposals this month.

Despite the rhetoric, Ukraine simply cannot join NATO with Crimea occupied and fighting in the Donbas because the alliance's collective security guarantee — that an attack on one ally is considered to be an attack on them all — would draw it into war if the country became a member.

Indeed, NATO’s help in the event of an invasion is unlikely to involve major military muscle.

“Ukraine is a very close partner,” Stoltenberg said. “We provide support to Ukraine. But Ukraine is not covered by NATO’s collective defense clause because Ukraine is not a NATO member.”

Blinken and Stoltenberg did say that the U.S. and NATO are willing to discuss arms control with Moscow, but that Putin cannot be permitted to impose restrictions on how the organization protects member countries close to Russia’s borders like Estonia, Latvia, Lithuania and Poland.

“We cannot end up in a situation where we have a kind of second-class NATO members; where NATO as an alliance is not allowed to protect them in the same way as we protect other allies,” he said.

The NATO-Russia Council was set up two decades ago. But NATO ended practical cooperation with Russia through the NRC in 2014 after it annexed Crimea. Wednesday’s meeting will be the first since July 2019. NATO officials say Russia has refused to take part in meetings as long as Ukraine was on the agenda.