General Valery Gerasimov, the head of Russia’s armed forces, called NATO’s eastward expansion a danger to the balance of power in Europe, addressing foreign military-diplomatic aides in Moscow on Thursday.

“The European continent has turned into a field of conflict between the West and Russia from a political and economic point of view,” summed up Mr. Gerasimov, chief of the general staff of national defense and deputy defense minister of Russia.

He pointed out that Sweden and Finland have asked to join the Atlantic alliance and that NATO forces stationed in Eastern Europe, the Baltic and the Black Sea have been strengthened.

General Gerasimov made no explicit reference to the Russian military invasion of Ukraine — the “special military operation,” in the Kremlin’s terminology — that began in late February 2022.

The conflict between the West and Russia cannot be ruled out to escalate, Mr. Gerasimov also noted, according to the Interfax news agency. Pre-existing confidence-building measures for security in Europe are losing their meaning, but the Russian side is following the rules to avoid surprises, he added.

Moscow is establishing new military administrations responsible for the Leningrad and Moscow regions in response to Finland’s accession to NATO, he added.

Russian President Vladimir Putin and Defense Minister Sergei Tsaigu have already hinted at the plans.

In his annual marathon television interview on Sunday, Mr. Putin referred, in a sibylish style, to Finland. “We had the most friendly and warm relations,” the president said, referring to the country with which Russia shares a 1,340-kilometer border. “There was no problem, but now there will be some,” he added, stressing that “we are creating a defense command in the Leningrad region and concentrating some military units there.”

The area around today’s Saint Petersburg retains its Soviet name.