Less than three months since Russian President Vladimir Putin launched a war to take control of Ukraine and halt NATO's expansion near his country's borders, its Nordic neighbor, Finland, is set to join the Western military alliance. That takes place as Russia’s troops are being pushed back in some key areas in Ukraine.

Finland's president and prime minister jointly announced early Thursday their intention for the country to join NATO "without delay," a significant shift in policy that is expected to be followed by Sweden in the coming days. It is the latest setback for the Kremlin and comes as the Russian military struggles to take full control of Mariupol while being hit by Ukrainian counterattacks in the northeast.