Russian Foreign Minister Sergei Lavrov said Thursday that the country is preparing for a "nightmare of military confrontation" if NATO continues to expand further eastward.

Speaking at a summit of the Organization for Security and Cooperation in Europe (OSCE) in Stockholm, Sweden, Lavrov suggested a new European security pact that would restrict NATO actions in the East, particularly in Ukraine. 

Russia has denied it is preparing for an attack against Ukraine and accused its neighbor of a military buildup. Ukraine said Russia has amassed more than 90,000 troops near the border. 

This is not the first time Russia warned of potential military action after NATO warnings. 

Russia on Tuesday warned NATO that expanding its military infrastructure in Ukraine would prompt an aggressive response, which included the possible deployment of missiles targeting Europe.

"Creating such threats [in Ukraine] would be red lines for us. But I hope it doesn't come to that. I hope that a sense of common sense, responsibility for both our countries and the world community will prevail," Russian President Vladimir Putin said Tuesday at an investment forum in Moscow.

Western countries have long raised alarms over Russian military activity near Ukraine. In mid-November, France warned Russia against the deteriorating security situation in Ukraine after the U.S. and European allies expressed concerns over Russian troop movements. 

Secretary of State Antony Blinken met with Lavrov in Sweden to de-escalate tensions about its military movements in Ukraine.

"It's now on Russia to de-escalate 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 OSCE summit.

Blinken added that there would be "serious consequences" if Russia sought conflict with Ukraine. President Joe Biden told reporters last week he would "in all probability" speak to Putin soon about military tension with Ukraine.

In 2014, sanctions were imposed on Russia by the U.S. and EU for invading Ukraine. The sanctions contributed to a financial crisis in Russia.