Opposition and anti-NATO groups in Montenegro have announced mass protests on Friday, when parliament is due to meet in the old royal capital to ratify the membership protocol.
Montenegro's parliament is set to ratify the NATO membership treaty on Friday, at a ceremonial session held in the old royal capital of Cetinje.
The vote will mark one of the final steps in the country’s long drawn-out accession process.
The law is likely to pass, as it only requires a simple majority of the 81 MPs, and the ruling coalition holds 42 seats.
Most opposition parties will boycott the vote in Cetinje, citing their frustrated demand for a referendum on the issue.
However, the former junior ruling Social Democratic Party, SDP, in opposition since last October, has announced it will attend the session and vote for NATO membership.
Announcing a mass rally against NATO rally in Cetinje, Montenegro's pro-Russia opposition Democratic Front has vowed to freeze membership of the alliance if it wins the next parliamentary election.
The Front said parliament’s approval of the accession treaty would be illegal, as a large majority of Montenegrin citizens strongly oppose NATO membership.
“We call on all citizens of Montenegro to join us tomorrow at the peaceful rally in Cetinje ... from where we will send a message to the rump parliament that the decision they will vote on is completely non-binding and void for the majority of Montenegro," Front leader Milan Knezevic said on Thursday.
The Front and other anti-NATO opposition parties, at a "shadow" assembly session on Wednesday held in the northern village Murino, which was hit by NATO airstrikes in 1999, also said they they will hold a referendum on Montenegro's status in NATO if they take power.
Prime Minister Dusko Markovic dismissed the opposition declarations as a "show", calling the event in Murino a “fete by the irresponsible opposition.
“Let them play, let them celebrate, organise an assembly, write a declaration ... let them have some and drink a beer," Markovic said, announcing tight security during the parliamentary session on Friday.
Montenegro joined NATO’s Partnership for Peace program, PfP, back in 2006.
It expected to become a member of NATO by the time of the alliance summit in Brussels in May.
However, besides procedures at home, ratification of Montenegro’s NATO accession protocol has had to pass through the parliaments of all 28 member states.
So far, the protocol has been confirmed by 26 members, but The Netherlands and Spain have yet to ratify the treaty.
The NATO membership bid has angered traditional ally Russia whose ties to Orthodox Christian Montenegro date back to the reign of Peter the Great.
Montenegro accused Russia of being behind a foiled coup attempt last October aimed at toppling the pro-Western government and derailing NATO accession. Moscow has denied the claims.
Referring to the Friday’s vote as a move "of the greatest historic importance," Montenegro‘s long-time former leader Milo Djukanovic on April 22 accused the opposition of "waving an empty gun" on orders from Russia.