STOCKHOLM — Secretary of State Antony Blinken urged Moscow on Thursday to abandon plans for a potential invasion of Ukraine, calling for a peaceful resolution to an intensifying showdown between Russia and the West.

Blinken’s warning in talks with Russian Foreign Minister Sergei Lavrov that Moscow could face dire consequences over Ukraine, and Lavrov’s vow to respond to any punitive measures from the West, underscored the obstacles to defusing the brewing crisis.

Their meeting on the margins of a European cooperation conference, Blinken’s second bilateral encounter with the Russian diplomat since becoming secretary of state, appeared to yield no substantive agreements but provided a means for the Biden administration to add force to its threat of “high-impact” economic retaliation should Russia launch an offensive against Ukraine.

“The best way to avert a crisis is through diplomacy,” Blinken, seated beside Lavrov, said at the start of what diplomats described as a “sober” half-hour meeting. “But, and again in the spirit of being clear and candid . . . if Russia decides to pursue confrontation, there will be serious consequences.”

The Biden administration has said a Russian incursion into Ukraine, nearly eight years after Moscow’s annexation of Crimea and the beginning of its support for an ongoing separatist conflict in eastern Ukraine, would undermine global principles of sovereignty and threaten security in Europe.

The discussion occurred a day after NATO nations concluded a summit in the Latvian capital, Riga, which officials said cemented an alliance position in support of Ukraine. NATO countries, however, provided few details of their planned response if Russian troops roll across the border.

Ukraine is not a NATO member but has voiced its desire to join the security bloc.

Leaders in Moscow have denied an invasion plan and instead accuse the West of threatening Russia by pushing weapons and troops ever closer to its borders.

“We, as President Putin has stated, do not want any conflicts,” Lavrov said alongside Blinken. “No one can guarantee their own security at the expense of the security of others. NATO’s extension . . . will infringe on our security.”

The meeting took place on the sidelines of an Organization for Security and Cooperation in Europe meeting outside the Swedish capital.

Earlier in the day, Blinken met with Ukrainian Foreign Minister Dmytro Kuleba, once again condemning Russia’s massing of troops and weaponry and promising support in seeking a diplomatic solution. The Ukrainian official asked partner nations to prepare a new package of deterrence measures that would “make President Putin think twice before resorting to military force.”

Speaking to reporters several hours after his meeting with Lavrov, Blinken said the discussion would set the stage for an upcoming call expected between Putin and President Biden. He declined to say how specifically he laid out possible retaliatory American steps but said his goal had been to convey U.S. concern and discuss ways to avert a deeper crisis.

“I think Moscow knows very well the universe of what’s possible,” he said.

Lavrov, in a separate press conference after the meeting, said Russia needed concrete agreements to ease tensions with NATO. He said Moscow would soon share its proposals for doing so.

“I don’t even want to speculate now that the West will refuse them. I think everyone has heard President Putin, realized that we are serious and now we’re putting them on paper,” he said.

“If new, like they say, sanctions ‘from hell’ follow, we will, of course, react,” he said. “We cannot help but react.”

In an indication of unresolved differences, each diplomat put the onus on the other side to de-escalate the situation. Both called for the implementation of the Minsk peace deal — an accord brokered by France and Germany in 2015 — but voiced divergent views on how that would occur.

Michael Kofman, director of Russia studies at the CNA research organization, said an expanded military engagement was not inevitable but that it appears more likely than at any time since the beginning of the conflict.

“The Russian red line has shifted beyond just the question of Ukraine in NATO, but to include NATO member military presence and defense cooperation in Ukraine,” he said.

The United States has provided military support to Ukraine, including equipment such as patrol boats and Javelin antitank missiles. Biden administration officials have also said they are looking for ways to strengthen military deterrence on NATO’s eastern flank.

“The U.S. faces a dilemma,” Kofman added. “Doing nothing is not an option, but we are not going to fight Russia over Ukraine, and signaling strong political commitments that we are not prepared to back meaningfully could have broader credibility consequences if the worst comes to pass.”

The disconnect was likewise apparent in the Russian Foreign Ministry’s depiction of the NATO summit, which it said “once again demonstrated the alliance’s fixation on fighting imaginary threats to the detriment of collective counteraction to real contemporary challenges.”

In a statement on its website, the ministry said that “dragging Kiev into the military orbit of the alliance, the de facto development by NATO of the military infrastructure of this country, the desire to turn it into a bridgehead of confrontation with Russia are fraught with serious negative consequences.”

One senior European diplomat who took part in the meetings in Riga and Stockholm said the most worrying aspect of the current Russian deployment along Ukraine’s border was that the Russian military would have “an extremely short warning time to begin any action.” The official spoke on the condition of anonymity to talk frankly about closed-door conversations with Blinken.

That timeline could give the United States and Ukraine’s European partners little to no opportunity to impose measures that might turn around Russia’s forces and stop full-scale war — meaning the time for effective action is now, the official said.

Khurshudyan reported from Moscow. Michael Birnbaum in Washington contributed to this report.