NATO foreign ministers on Wednesday decided to invite Montenegro to become the 29th member of their alliance, despite concerns in Russia over the move.
"NATO's open door policy has helped to spread security, stability and the democratic values for which the alliance stands," NATO Secretary General Jens Stoltenberg said.
Montenegro will be the third nation from the Western Balkans to join NATO after Albania and Croatia. The move is a positive signal for the entire region, Deputy Prime Minister Igor Luksic said.
"This is indeed a great day for my country, I believe a well-deserved one," he told NATO ministers in Brussels. "The invitation to Montenegro is great news for the Western Balkans as well, for the strengthening of its security and stability."
Russia, however, had warned that the move would be harmful to European security and would further strain relations between NATO and Moscow, which are already at a low point over the crisis in Ukraine.
Luksic promised that his country would steadfastly continue implementing reforms, for instance when it comes to fighting corruption or improving the defence sector.
"We are fully aware that the invitation is not the end of the process, but the beginning of a new one," he said. "We're determined to constantly improve and work tirelessly, not to please others but to change our society for the better."
Accession talks and a parliamentary ratification process in existing NATO member states will now take place before the nation, once part of Yugoslavia, can formally join.
Bosnia, Georgia and Macedonia are also keen to become members of the alliance, but have not made enough progress so far. The NATO ministers will also comment Wednesday on their membership prospects.
Later in the day, the ministers will meet their Ukrainian counterpart Pavlo Klimkin. His country had also once aspired to join NATO, but the ambition has been put on ice.
"We will reconfirm our political support to Ukraine and we will review our practical support to help Ukraine modernize its command and control, cyber and logistic capabilities," Stoltenberg said Monday.
The ministers will discuss the Minsk ceasefire deal for eastern Ukraine, which was agreed to in February and was supposed to be implemented by the end of the year.
"Recently we have seen an upsurge in the violations, more fighting," Stoltenberg noted. "This is of course something which causes concern."