HELSINKI — Russia has issued fresh threats of a possible military response should any of the unaligned Nordic neighboring states opt to join NATO.

This latest rhetoric from Moscow has drawn a swift and robust reply from Sweden.

"These warnings are unnecessary and uncalled for. In Sweden we make our own choices and decisions about foreign, defense and security policy," Swedish Prime Minister Stefan Löfven said.

The Finnish government also said it would not allow Russia to dictate its foreign policy or NATO-centered decision-making process.

Russia's Foreign Minister Sergey Lavrov said Moscow would be "compelled to take action" if Sweden became part of NATO's infrastructure.

"While it is every country's right to decide what form of national security it has, we must make it understood that if NATO's military infrastructure approaches Russia's borders, we will be required to take the necessary military-technical action," Lavrov said.

The Swedish Moderate Party's foreign policy spokeswoman Karin Enström said Russia has no right to intervene in the political decision-making systems of democratic, nonaligned Nordic states.

"On the one hand the Russian foreign minister states that each country has the right to set its own security policy, and in the same breath insinuates that there could be military consequences. We need to have clarity from Russia as to what this all means," Enström, a former minister of defense, said.

Moscow has become increasingly agitated over Finland's and Sweden's deepening military relations with NATO. In recent months, this collaboration has developed far beyond Partnership for Peace (PfP) mechanisms.

Russia is particularly concerned over Finland's closer military relationship with NATO. Unlike Sweden which does not have a border with Russia, Finland has an 833 mile frontier with its Eastern neighbor.

Russia will respond to unaligned Nordic states joining NATO by reinforcing its military capabilities on its northern and northwestern borders, according to Evgeny Serebrennikov, the deputy chairman of the Russian Federation Council's Committee on Defense and Security.

"If Sweden joins NATO, we will increase the size of the Northern Fleet and strengthen our air defense systems. Russia is nearing completion on the development of a new generation of missiles that are impregnable to NATO forces," Serebrennikov said.

Neither Finland or Sweden have given clear signals of intent to join NATO. Despite this, Russia continues to use "bullying tactics" to dissuade both countries from joining the alliance, said Piet Kessler, a political analyst based in The Hague, Netherlands.

"Russia certainly doesn't want Finland in NATO. This would raise the prospect of having alliance forces near its border. The new threats are unusual. Moscow has shown a willingness to maintain and grow a good relationship with Norway, a Nordic state in NATO that also has a sizable border with Russia," Kessler said.

Moscow's unease over Finland's deepening military ties with NATO has grown against the backdrop of a Finnish government commissioned strategic report that asserts Finland's "capacity" to join NATO, independently or in a coordinated action with Sweden, should it decide.

Titled "Effects of Finland's possible Nato membership," the report's panel of international experts warned that Finland risked triggering a serious crisis with Russia if it joined NATO.

The report will be used in the drafting of Finland's impending foreign and security policy strategy.

"Any future decision to join NATO would be subject to a referendum on the issue. I do not believe this report will lead to any pressure from Russia," Finnish Prime Minister Juha Sipilä said. "This is the time to comprehensively and openly assess what the reaction from Russia might be, if Finland or Sweden join NATO."

The Finnish report concludes that the impact on Finland of joining NATO as a full member would be considerably more benign if Sweden and Finland were to agree on a coordinated "joint leap" into the alliance.

Sweden's Defence Minister Peter Hultqvist described the Finnish report as a "useful and timely analysis," noting that both Finland and Sweden would benefit from developing a common approach to security policy.

However, Hultqvist emphasized that Sweden's present socialist government had no plans to alter the country's nonaligned status.

The ruling Social Democrats, to which Hultqvist belongs, oppose NATO membership. Membership of the alliance is supported by Sweden's center and conservative parties.

Finland's deepening military collaboration with the alliance will be expanded in June when the NATO-led Baltic Operations (BALTOPS) amphibious landing exercises, which include special forces operations, are extended to the Finnish mainland for the first time.

Swedish forces will also take part in BALTOPS. The multinational force land, sea and air exercises will involve around 4,500 troops.