President Joe Biden spoke with the respective leaders of Sweden and Finland Friday, according to the White House, and voiced his support of both countries joining the North Atlantic Treaty Organization (NATO).

Citing a White House readout of the 40-minute conference call with Swedish Prime Minister Magdalena Andersson and Finnish President Sauli Niinistö, President Biden "underscored his support for NATO's open door policy and for the right of Finland and Sweden to decide their own future, foreign policy, and security arrangements."

The readout added: "The leaders also discussed the close partnership among our countries across a range of global issues, based on our common values and interests. They reiterated their shared commitment to continued coordination in support of Ukraine and the Ukrainian people affected by the war."

President Biden's call follows increased speculation of Sweden and/or Finland joining NATO soon, in the wake of Russia's full-scale invasion of Ukraine, which began on Feb. 24.

It also comes two-plus weeks after NATO Secretary-General Jens Stoltenberg suggested that Finland and Sweden would be ideal alliance fits.

"It's their decision," Stoltenberg said. "But if they decide to apply, Finland and Sweden will be warmly welcomed, and I expect that process to go quickly."

The 30-nation NATO group, which was formed in 1949 to counter the geopolitical efforts of the Soviet Union during the Cold War era, includes world powers such as the United States, France, Germany, Italy, Poland, Canada, Spain, the United Kingdom, and the Czech Republic.

Secretary of State Antony Blinken will reportedly meet with the foreign ministers of Sweden, Finland, and NATO members in Berlin this weekend, with the intent of laying the groundwork for Sweden and Finland joining the alliance.

The recent courting of Finland has particularly angered Russian officials, so much that the Kremlin has previously vowed to take "retaliatory steps" should Finland commit to a NATO membership.

If Finland joins the alliance, six NATO members would subsequently share direct border access with Russia: Latvia, Estonia, Norway, Lithuania, and Poland.

(Sweden is nestled between Norway and Finland.) 

Ukraine isn't a NATO member, but a number of alliance countries have supported the Ukrainian forces during their war with Russia.

According to NATO statistics, the unified group currently shares 754 border miles with Russia; if Finland joins in, the defensive alliance would extend to 832 miles.

• NATO Moves Into Finland, As Russia Threatens Response
• Does US Risk Provoking Putin With Ukraine Intelligence Sharing?