CNN  — 

US Secretary of State Antony Blinken and Russian Foreign Minister Sergey Lavrov met Thursday in Stockholm, Sweden, amid growing concern among Western powers that Russia is seeking to invade Ukraine.

Blinken said he and Lavrov would report the details of their meeting back to President Joe Biden and President Vladimir Putin and that the two presidents “may have the opportunity to speak directly in the near future.”

Until then, he said it’s Russia’s responsibility to defuse the growing tension about its military movements and disinformation targeting Ukraine.

“It’s now on Russia to deescalate the current tensions by reversing the recent troop buildup, returning forces to normal peacetime positions, and refraining from further intimidation and attempts to destabilize Ukraine,” Blinken said at a press conference at the Organization for Security and Cooperation in Europe summit.

US officials tell CNN that plans for a conversation between Biden and Putin haven’t been finalized, but that work has been underway to set up a call as Russian troops amass at the Ukraine border.

Biden told reporters last week he would “in all probability” speak to Putin soon about the situation in Ukraine. He has said direct communication with Putin is the best way to avoid conflict between the two countries.

‘Deep concerns’

The last publicly announced phone call between Biden and Putin came in July, about a month after their in-person summit in Geneva.

Blinken and Lavrov met on the sidelines of the OSCE summit. Their 30-minute conversation did not yield a concrete path forward, but both sides agreed to continue diplomatic conversations, a senior US State Department official told reporters traveling with the top US diplomat.

Blinken also held a bilateral meeting earlier Thursday with the Ukrainian Foreign Minister Dmytro Kuleba, at which the top US diplomat reiterated Washington’s “unwavering commitment to Ukraine’s territorial integrity, sovereignty and its independence.”

In remarks to the press after meeting with Lavrov, Blinken said he had “made very clear our deep concerns and our resolve to hold Russia responsible for his actions, including to work with European allies to impose severe costs and consequences on Russia, if it takes further aggressive action against Ukraine.”

The meeting comes a day after Blinken issued the most forceful US warning yet to Russia about any attempt to destabilize or invade Ukraine. Blinken had warned that there will be “severe consequences” for any Russian military action in Ukraine and that the US would “respond resolutely, including with a range of high impact economic measures that we’ve refrained from using in the past.”

Blinken did not lay out the “serious consequences” he has threatened if Russia invades Ukraine, according to the senior US State Department official.

The official, who described Blinken’s meeting with Lavrov as sober and professional, said the meeting resulted in an agreement to continue diplomatic conversations and that the US was able to make clear their concerns about the Russian military buildup.

According to the State Department, Blinken “addressed Russia’s aggression towards Ukraine, including its military movements near Ukraine’s borders” and “reiterated the United States’ call for Russia to pull back its forces and return to a peacetime posture” and to adhere to the 2015 Minsk agreements – an effort to end the conflict in eastern Ukraine – and a ceasefire in the Donbas region.

The Minsk Protocol was written by Ukraine, Russia and the OSCE with France and Germany mediating. On Thursday, Blinken said he told Lavrov that the US was ready to get involved and had already offered to do so with Ukraine’s top diplomat.

“And as with Foreign Minister Kuleba, I also made clear The United States is prepared to work with both parties to support a diplomatic resolution through implementation of Minsk agreements in any way that we can,” he said.

Combat troops

Pentagon spokesman Ned Price said in his readout that Blinken “underscored that the best path forward is diplomacy in conjunction with the full implementation of the Minsk agreements, a process the United States is willing and ready to support.”

The US and NATO say Russia is increasing the number of combat troops near its border with Ukraine, while the Kremlin has repeatedly denied that Russia plans to invade Ukraine and sees NATO support for the country as a threat on Russia’s western border.

In his own remarks to the press after meeting with Blinken, Lavrov stressed that although Russia does “not want any conflicts” with NATO over Ukraine, it maintains the “right to choose ways to ensure its legitimate security interests.”

“And let’s not forget, of course, the proclaimed principle of indivisibility and security, including in the OSCE, in the NATO Council of Russia, which says that no one has the right to strengthen their security at the expense of the security of others,” he said, also adding that “the further advance of NATO to the East will definitely affect the fundamental interests” of Russia’s security.

The United States, meanwhile, warned again that there would be “serious consequences” if Russia engages to “pursue confrontation” with Ukraine.

On Thursday, Blinken told summit attendees that the US holds “deep concerns about Russia’s plans for renewed aggression against Ukraine.”

This aggression would “move us in exactly the opposite direction,” Blinken said, stressing “it’s simply not in anyone’s interest.”

He added that “the best way to avert the crisis is through diplomacy,” calling on Russia to abide by the Minsk peace agreements. The interpretation of Minsk and other core OSCE documents emerged as a sticking point between the two countries, with Lavrov saying it “is clear” that the US and Russia interpret them in “different ways.”

Blinken criticized Russia’s adherence to the Helsinki Final Act, a multilateral agreement dating back to 1975. That non-binding diplomatic accord recognized the inviolability of national borders created after World War II and the importance of noninterference in a nation’s internal affairs, but Russia also saw it as implicitly recognizing its hegemony in Eastern Europe. Blinken said Russia “continues to violate the Helsinki principles and repeatedly obstructs the work of this organization.”

Despite the accusations, the two officials recognized the importance of dialogue, with Lavrov acknowledging “the importance of our two states for global stability and for security, including in the Euro-Atlantic area.”

During their private meeting, other subjects like Iran and the Nagorno-Karabakh region were also raised, but there was no discussion of the Russia-backed coup alleged by Ukraine’s president.

Price said Blinken raised the cases of two Americans detained in Russia – Paul Whelan and Trevor Reed – “and underscored the priority we attach to their prompt release.”

“The Secretary and the Foreign Minister noted the importance of continued coordination on issues in the bilateral relationship and where interests are aligned, including when it comes to blocking Iran’s pathways to a nuclear weapon,” he said.

The OSCE summit comes on the heels of a meeting of NATO foreign ministers in Latvia that was dominated by concerns over recent events in Belarus and Russia’s intentions in Ukraine.

Speaking Wednesday after the meeting in Latvia, Blinken said the US and its NATO partners were prepared to impose costs for further Russian aggression against Ukraine and were preparing for “all contingencies” as Russia continues to make troubling moves.

While Blinken hasn’t detail what those penalties will be, NATO Secretary General Jens Stoltenberg said in a Wednesday interview with CNN’s Jim Sciutto that the alliance has “a wide range of options: economic sanctions, financial sanctions, political restrictions.”

Putin called Wednesday for specific agreements that would rule out any further NATO expansion eastwards and deployment of its weaponry close to Russia’s borders.

On Tuesday, the Russian President said NATO military expansion close to Russian borders and any deployment of missile systems in Ukraine would be crossing a “red line.”

CNN’s Alex Marquardt reported from Stockholm, Jennifer Hansler reported from Washington, Niamh Kennedy from London and Anna Chernova from Moscow. CNN’s Veronica Stracqualursi, Michael Conte, Kevin Liptak and Nicole Gaouette contributed from Washington.