Swedish Prime Minister Magdalena Andersson, left, and Finnish Prime Minister Sanna Marin pose for photographers ahead of a meeting on whether to seek NATO membership, in Stockholm, Sweden, Wednesday, April 13, 2022. Paul Wennerholm/TT via AP

HELSINKI — European Union nations Finland and Sweden reached important stages Wednesday on their way to possible NATO membership as the Finnish government issued a security report to lawmakers and Sweden’s ruling party initiated a review of security policy options.

Russia’s invasion of Ukraine on Feb. 24 triggered a surge in support for joining NATO in the two traditionally militarily non-aligned Nordic countries, with polls showing a majority of respondents willing to join the alliance in Finland and supporters of NATO in Sweden clearly outnumbering those against the idea.

Finland, a country of 5.5 million, shares the EU’s longest border with Russia, a 1,340-kilometer (833-mile) frontier. Sweden has no border with Russia.

Russia, for its part, has warned Sweden and Finland against joining NATO, with officials saying it would not contribute to stability in Europe. Officials said Russia would respond to such a move with retaliatory measures that would cause “military and political consequences” for Helsinki and Stockholm. One of Russian President Vladimir Putin’s reasons for invading Ukraine was that the country refused to promise that it would not join NATO.

Finnish Prime Minister Sanna Marin, speaking Wednesday in Stockholm in a joint news conference with her Swedish counterpart Magdalena Andersson, said Finland is ready to make a decision on NATO “within weeks” rather than months following an extensive debate in the 200-seat Eduskunta legislature.

Marin stressed that Finland and Sweden, two neighboring Nordic countries which have close economic, political and military ties, will make independent decisions regarding their security policy arrangements, including whether to join NATO.

“But we do that with a clear understanding that our choices will affect not only ourselves but our neighbors as well,” Marin said, adding that she would prefer seeing both Finland and Sweden becoming NATO members.

Andersson said Sweden and Finland would maintain “a very close dialogue and have a very straightforward and honest discussions” in the coming weeks over their countries respective choices on NATO.

The only real option to NATO membership could be an enhanced bilateral military cooperation added with the United States and Nordic NATO member Norway, Finnish experts have said.

Marin and Andersson lead the ruling Social Democratic Parties in their respective countries. The parties are expected to announce their NATO views in early and late May, respectively. Parliaments in both countries are ready to finally decide the matter — something that could happen in Finland in late May and a bit later in Sweden.

Complicating things in Sweden is the general election in September, which is likely to be dominated by the NATO issue.

In Finland, President Sauli Niinisto said he was convinced that his country’s decision on NATO will be ready well ahead of NATO’s June 29-30 summit in Madrid, Spain.

On Wednesday, the Finnish government issued a much-awaited report on changes in Finland’s security environment that lawmakers will start debating after the Easter break. The report addresses the pros and cons of Finland’s possible membership in NATO, focusing on supply threats, economic effects, cybersecurity and hydrid threats.

“The war started by Russia endangers security and stability in entire Europe,” Finnish Foreign Minister Pekka Haavisto said as he presented the report. “Russia’s attack on Ukraine will have a long-lasting impact on our own security environment. Trust in Russia has plummeted.”

Andersson said Wednesday that the Swedish government is working on a security environment analysis together with all parties in the 349-seat Riksdag legislature. She said the report is due May 31 but could be finished earlier. In addition, Andersson’s Social Democratic Party has initiated its own separate review of Sweden’s security environment.