MOSCOW — It might seem as if little has changed for Russia and the United States, two old adversaries seeking to undercut each other around the world.

Russian nuclear-capable missiles have been spotted on the move near Ukraine, and the Kremlin has signaled the possibility of a new intervention there. It has tested hypersonic cruise missiles that skirt American defenses and cut all ties with the American-led NATO alliance. After a summer pause, ransomware attacks emanating from Russian territory have resumed, and in late October, Microsoft revealed a new Russian cybersurveillance campaign.

Since President Biden took office nine months ago, the United States has imposed sweeping new sanctions on Russia, continued to arm and train Ukraine’s military and threatened retaliatory cyberattacks against Russian targets. The American Embassy in Moscow has virtually stopped issuing visas.

As world leaders met at the Group of 20 summit this weekend in Rome, Mr. Biden did not even get the chance to hash things out with his Russian counterpart face to face because President Vladimir V. Putin, citing coronavirus concerns, attended the event remotely.

Yet beneath the surface brinkmanship, the two global rivals are now also doing something else: talking.

The summit between Mr. Biden and Mr. Putin in June in Geneva touched off a series of contacts between the two countries, including three trips to Moscow by senior Biden administration officials since July, and more meetings with Russian officials on neutral ground in Finland and Switzerland.

There is a serious conversation underway on arms control, the deepest in years. The White House’s top adviser for cyber and emerging technologies, Anne Neuberger, has engaged in a series of quiet, virtual meetings with her Kremlin counterpart. Several weeks ago — after an extensive debate inside the American intelligence community over how much to reveal — the United States turned over the names and other details of a few hackers actively launching attacks on America.

Now, one official said, the United States is waiting to see if the information results in arrests, a test of whether Mr. Putin was serious when he said he would facilitate a crackdown on ransomware and other cybercrime.

Officials in both countries say the flurry of talks has so far yielded little of substance but helps to prevent Russian-American tensions from spiraling out of control.

A senior administration official said the United States was “very cleareyed” about Mr. Putin and the Kremlin’s intentions but thinks it can work together on issues like arms control. The official noted that Russia had been closely aligned with the United States on restoring the Iran nuclear deal and, to a lesser degree, dealing with North Korea, but acknowledged that there were many other areas where the Russians “try to throw a wrench into the works.”

Mr. Biden’s measured approach has earned plaudits in Russia’s foreign policy establishment, which views the White House’s increased engagement as a sign that America is newly prepared to make deals.

“Biden understands the importance of a sober approach,” said Fyodor Lukyanov, a prominent Moscow foreign policy analyst who advises the Kremlin. “The most important thing that Biden understands is that he won’t change Russia. Russia is the way it is.”

For the White House, the talks are a way to try to head off geopolitical surprises that could derail Mr. Biden’s priorities — competition with China and a domestic agenda facing myriad challenges. For Mr. Putin, talks with the world’s richest and most powerful nation are a way to showcase Russia’s global influence — and burnish his domestic image as a guarantor of stability.

“What the Russians hate more than anything else is to be disregarded,” said Fiona Hill, who served as the top Russia expert in the National Security Council under President Donald J. Trump, before testifying against him in his first impeachment hearings. “Because they want to be a major player on the stage, and if we’re not paying that much attention to them they are going to find ways of grabbing our attention.”

For the United States, however, the outreach is fraught with risk, exposing the Biden administration to criticism that it is too willing to engage with a Putin-led Russia that continues to undermine American interests and repress dissent.

European officials worry Russia is playing hardball amid the region’s energy crisis, holding out for the approval of a new pipeline before delivering more gas. New footage, circulated on social media on Friday, showed missiles and other Russian weaponry on the move near Ukraine, raising speculation about the possibility of new Russian action against the country.

In the United States, it is the destructive nature of Russia’s cybercampaign that has officials particularly concerned. Microsoft’s disclosure of a new campaign to get into its cloud services and infiltrate thousands of American government, corporation and think tank networks made clear that Russia was ignoring the sanctions Mr. Biden issued after the Solar Winds hack in January.

But it also represented what now looks like a lasting change in Russian tactics, according to Dmitri Alperovitch, the chairman of the research group Silverado Policy Accelerator. He noted that the move to undermine America’s cyberspace infrastructure, rather than just hack into individual corporate or federal targets, was “a tactical direction shift, not a one-off operation.”

Russia has already found ways to use Mr. Biden’s desire for what the White House refers to as a more “stable and predictable” relationship to exact concessions from Washington.

When Victoria Nuland, a top State Department official, sought to visit Moscow for talks at the Kremlin recently, the Russian government did not immediately agree. Seen in Moscow as one of Washington’s most influential Russia hawks, Ms. Nuland was on a blacklist of people barred from entering the country.

But the Russians offered a deal. If Washington approved a visa for a top Russian diplomat who had been unable to enter the United States since 2019, then Ms. Nuland could come to Moscow. The Biden administration took the offer.

Ms. Nuland’s conversations in Moscow were described as wide ranging, but in the flurry of talks between the United States and Russia, there are clearly areas the Kremlin does not want to discuss: Russia’s crackdown on dissent and the treatment of the imprisoned opposition leader Aleksei A. Navalny have gone largely unaddressed, despite the disapproval that Mr. Biden voiced on the matter this year.

While Mr. Biden will not see Mr. Putin in person at the Group of 20 summit in Rome or at the Glasgow climate summit, Dmitri S. Peskov, Mr. Putin’s spokesman, said in October that another meeting this year “in one format or another” between the two presidents was “quite realistic.”

“Biden has been very successful in his signaling toward Russia,” said Kadri Liik, a Russia specialist at the European Council on Foreign Relations in Berlin. “What Russia wants is the great power privilege to break rules. But for that, you need rules to be there. And like it or not the United States is still an important player among the world’s rule setters.”

The most notable talks between Russian and American officials have been on what the two call “strategic stability” — a phrase that encompasses traditional arms control and the concerns that new technology, including the use of artificial intelligence to command weapons systems, could lead to accidental war or reduce the decision time for leaders to avoid conflict. Wendy Sherman, the deputy secretary of state, has led a delegation on those issues, and American officials describe them as a “bright spot” in the relationship.

Working groups have been set up, including one that will discuss “novel weapons” like Russia’s Poseidon, an autonomous nuclear torpedo.

While Pentagon officials say that China’s nuclear modernization is their main long-term threat, Russia remains the immediate challenge. “Russia is still the most imminent threat, simply because they have 1,550 deployed nuclear weapons,” Gen. John E. Hyten, who will retire in a few weeks as the vice chairman of the Joint Chiefs of Staff, told reporters on Thursday.

In other contacts, John F. Kerry, Mr. Biden’s climate envoy, spent four days in Moscow in July. And Robert Malley, the special envoy for Iran, held talks in Moscow in September.

Aleksei Overchuk, a Russian deputy prime minister, met with Ms. Sherman and Jake Sullivan, Mr. Biden’s national security adviser — talks that Mr. Overchuk described as “very good and honest” in comments to Russian news media.

Mr. Putin, finely attuned to the subtleties of diplomatic messaging after more than 20 years in power, welcomes such gestures of respect. Analysts noted that he recently also sent his own signal: Asked by an Iranian guest at a conference in October whether Mr. Biden’s withdrawal from Afghanistan heralded the decline of American power, Mr. Putin countered by praising Mr. Biden’s decision and rejecting the notion that the chaotic departure would have a long-term effect on America’s image.

“Time will pass and everything will fall into place, without leading to any cardinal changes,” Mr. Putin said. “The country’s attractiveness doesn’t depend on this, but on its economic and military might.”

Anton Troianovski reported from Moscow, and David E. Sanger from Washington.