"We congratulate the government and people for this achievement, this is a very good day for Montenegro, a good day for the Western Balkans and the whole alliance, " NATO Secretary General Jens Stoltenberg said at the foreign ministers North-Atlantic Council meeting on Wednesday in Brussels.
Anti-government protesters will take to the streets of Podgrica again on Sunday, repeating their call for a transition government to replace Prime Minister Milo Djukanovic.
US Vice-President Joseph Biden told Montenegrin Prime Minister Milo Djukanovic by phone on Monday that Washington supports NATO membership for Montenegro, "provided that Montenegro continues pursuing reforms and boosts popular support" for joining.
The 28-member alliance is due to make a decision on Montenegro's membership in December.
Austrian Foreign Minister Sebastian Kurtz on Friday said recent attacks on journalists in the country were "very regrettable and should not happened".
Speaking after a meeting with Montenegrin Foreign Minister Igor Luksic in Podgorica, he said he had came to Montenegro primarily to meet civil society groups and the media and hear what they have to say.
More than half the senior officials in the leadership of the ruling Democratic Party of Socialists, DPS, will be replaced by young activists, the party announced on Thursday.
Montenegro's ruling party congress, scheduled for next week, is expected to reaffirm Prime Minister Milo Djukanovic's position as leader and tighten party discipline.
Djukanovic, a former communist, has led Montenegro for almost 25 years. He is seeking his seventh mandate as leader of a party that has been in power without interruption since the beginning of the nineties.
Germany's Foreign Minister pledged Berlin's strong support for Montenegro's strategic foreign policy goals of EU and NATO membership, hailing the country as "a success story in the region.
"I would like to see more examples like Montenegro," Steinmeier said on Wednesday after a meeting in Berlin with the Montenegrin Prime Minister, Milo Djukanovic.
The veteran leader of Montenegro is to meet German Chancellor Angela Merkel during his official visit to Berlin on Wednesday, mainly to discuss the country's prospects of joining NATO and the EU.
NATO secretary-general Jens Stoltenberg said on Wednesday that Montenegro has made "real progress towards membership".
Speaking after talks in Brussels with Montenegrin Prime Minister Milo Djukanovic, Stoltenberg said Podgorica had "introduced substantial reforms" to improve the the rule of law in the country as well as the defence and intelligence sectors.