WASHINGTON — Seeking to head off a potential assault on Ukraine, Secretary of State Antony J. Blinken will meet with Russia’s foreign minister on Friday as the two sides explore whether there is still a diplomatic path to avoiding a conflict in Eastern Europe.

The talks will try to break a deadlock that was thrown into sharp relief last week when a series of three negotiating sessions between Russia and the West ended in an impasse. The thorniest issue was Russia’s demand that NATO pledge not to expand eastward, a condition that the United States and Western Europe have rejected.

The White House said Tuesday that Mr. Blinken would “urge Russia to take immediate steps to de-escalate.”

“We’re now at a stage where Russia could at any point want an attack in Ukraine,” the White House press secretary, Jen Psaki, said, “and what Secretary Blinken is going to do is highlight very clearly there is a diplomatic path forward.”

Mr. Blinken departed on Tuesday for Kyiv, the Ukrainian capital, where he will meet with President Volodymyr Zelensky of Ukraine in a show of American support on the brink of what U.S. officials fear is an imminent Russian invasion.

Mr. Blinken will follow that visit with stops in Berlin on Thursday before meeting with Russia’s foreign minister, Sergey V. Lavrov, in Geneva the next day, a senior State Department official said on Tuesday.

The official warned that Russia — which has assembled as many as 100,000 troops along Ukraine’s eastern borders — could launch an attack at any time.

A senior Russian diplomat warned last Thursday that the talks were reaching a “dead end.” The Kremlin signaled it could refuse to engage in further negotiations and instead take unspecified “military-technical” measures to assure its security, insisting Russia would not allow the West to bog it down in long-running negotiations.

That Mr. Lavrov will meet with Mr. Blinken on Friday indicates that Russia is prepared for at least one more round of diplomacy.

The two spoke by phone on Tuesday before Mr. Blinken’s departure for Kyiv. In the call, Mr. Lavrov rejected the idea that Russia was planning to attack Ukraine and insisted that it was up to Kyiv to calm tensions, according to a description of the call published by the Russian Foreign Ministry.

“The minister urged the secretary of state not to replicate speculation about allegedly impending ‘Russian aggression,’” the Foreign Ministry said.

The State Department has not described Mr. Blinken’s agenda for the meeting with his long-serving Russian counterpart.

Russian officials have said that they are expecting a written American response to demands that Russia made weeks ago about NATO’s presence in Eastern Europe. The Russian Foreign Ministry said Mr. Lavrov told Mr. Blinken in their phone call that Moscow was expecting “article-by-article” comments from the United States on Russia’s proposals.

The State Department official would not say whether Mr. Blinken would provide such a response, and said it remained unclear whether Moscow was serious about finding a diplomatic solution to the crisis.

In its proposals published last month on what Russia calls “security guarantees” it needs from the West, Russia called for a series of measures that would effectively restore Russia’s sphere of influence close to Soviet-era lines, before NATO expanded into Eastern Europe.

And while Russia’s troop buildup is most obviously threatening Ukraine, analysts and Western officials believe that if it abandons diplomacy, the Kremlin could also take other steps — like repositioning its nuclear missile arsenal — to more directly threaten the United States and Western Europe.

“This is a serious matter,” Mr. Lavrov said at a news conference alongside his German counterpart, Annalena Baerbock, in Moscow on Tuesday. “Drawing things out before reaching concrete agreements on this score is not working.”

In an effort to deter Mr. Putin, the United States and its allies have promised to impose punishing sanctions against Russia if it attacks Ukraine. In Germany on Tuesday, the country’s new chancellor, Olaf Scholz, warned Russia of “high costs” in the event of military action.

In particular, Russia is eager for Germany to approve the Nord Stream 2 pipeline that would transport Russian gas to Western Europe, enhancing Moscow’s leverage over European energy. Asked about Nord Stream 2, Mr. Scholz said “everything will have to be discussed if it comes to a military intervention in Ukraine.’’

Mr. Blinken will meet in Berlin with German officials, as well as British and French diplomats as the United States and Europe work to coordinate severe economic sanctions to punish any Russian incursion into Eastern Ukraine, where Moscow has been supporting a separatist insurgency for years.

“There’s a diplomatic path forward,” Ms. Psaki said, adding: “It is up to the Russians to determine which path they’re going to take, and the consequences will be severe if they don’t take the diplomatic path.”

Michael Crowley reported from Washington, and Anton Troianovski from Moscow.