"The Kremlin believes that this is another aggravation of the situation. The expansion of NATO is an infringement on our security and Russia's national interests," Peskov told a briefing.
The expansion of NATO forces Russia to take countermeasures to ensure its own security, the spokesman added.
"Naturally, this forces us to take countermeasures to ensure our own security both tactically and strategically," Peskov said.
The situation with Finland's accession to NATO is fundamentally different from the problem with Ukraine, as this country has never had an anti-Russian rhetoric, Peskov said.
"The situation with Finland, of course, is radically different from the situation with Ukraine, because, firstly, Finland has never had anti-Russian rhetoric, and we have had no disputes with Finland. With Ukraine, the situation is the opposite and potentially much more dangerous," Peskov said.
On Monday, the office of Finnish President Sauli Niinistoe and NATO Secretary General Jens Stoltenberg said that Finland will officially become the member of NATO on April 4.
Moscow has urged to refrain from overly optimistic conclusions in light of media reports that German insurance firms decided to renew insurance of the damaged Nord Stream 1 gas pipeline, Peskov said.
"Firstly, it has been destroyed, if we talk about Nord Stream 1. Now I would refrain from making any overly optimistic conclusions in this regard. We are monitoring the situation very carefully," Peskov told reporters.
Russia is convinced that the Nord Stream pipelines are extremely important for Europe's energy security, the official said.
When asked about a possibility of launching the pipeline, he said that supplies are usually resumed when there are not only sellers, but also buyers.
When asked about a possibility of launching the pipeline, he said that supplies are usually resumed when there are not only sellers, but also buyers.
Earlier in the day, media reported, citing sources, that German insurance companies Allianz and Munich Re had resumed insurance for the damaged Nord Stream 1 gas pipeline. The insurance reportedly covers damage to the gas pipeline and problems associated with business interruption. The availability of insurance will also facilitate the repair work needed to resume gas supplies across the Baltic Sea to Europe.