Montenegro became the 29th member of the storied North Atlantic Treaty Organization, or NATO, on Monday, prompting congratulations from other member states and threats of reprisal from NATO’s long time opponent, Russia.

Montenegrin Prime Minister Duško Marković marked the occasion by attending a State Department ceremony in Washington D.C., which he followed up by meeting with American Vice President Mike Pence at the White House.  The Prime Minister did not meet with President Trump during his visit.

Like many other NATO nations, Montenegro is not currently spending the required two percent of its gross domestic product (GDP) on defense, a requisite for all members that only five nations currently fulfill, but Marković explained to Pence that his nation has set into a motion a plan to reach that goal by 2024.

U.S. Under Secretary of State Thomas Shannon commended Marković and his nation’s government for the decision to join the alliance, a significant departure from the tiny nation’s historically Russian friendly past.  Montenegro, an ex-Yugoslav republic that once held Russia among its most important allies, has made dramatic shift toward the West, and now hopes to join the European Union as well.  Shannon explained that Montenegro “should be commended … for asserting its sovereign right to choose its own alliances even in the face of concerted foreign pressure.”

“As President Trump said in his February 28th remarks to a joint session of Congress, ‘America respects the right of all nations to chart their own path,'” Shannon said.

NATO Secretary-General Jens Stoltenberg echoed those sentiments in his own statement, saying the addition of Montenegro will add to international peace and security.

(It) sends a signal to other states that seek membership that if a country truly reforms, if it promotes democracy, strengthen the rule of law, modernizes its armed forces, and contributes to our collective defense, it too can join the alliance,” he said.

The last nations to join NATO were Albania and Croatia in April of 2009.