Legislators in Montenegro have ratified the membership treaty with Nato, taking a historic turn towards the West despite protests from Russia and the pro-Russian opposition.

All 46 legislators present at the session voted in favour of Montenegro becoming a Nato member. The parliament has 81 seats but pro-Russian opposition members boycotted the session in the historic capital of Cetinje.

Prime minister Dusko Markovic said earlier in a speech that Nato membership would present a guarantee for Montenegro's future security, economic progress and regional stability.

Several hundred pro-Russian opposition supporters rallied in protest against the vote. Demonstrators burned a Nato flag and chanted "Treason" before peacefully dispersing.

Moscow has been angered by Nato expansion in Montenegro, which is Russia's traditional zone of interest.

Montenegro has accused Russia of being behind a foiled election-day coup in October allegedly designed to throw the country off its path toward Nato. Russia has denied involvement.

Montenegro has a small military of around 2,000 troops, but it is strategically positioned to give Nato full control over the Adriatic Sea. The other Adriatic nations - Albania, Croatia and Italy - are already in the alliance.

"This assembly and its members have a historic privilege to make a decision that will be remembered as long as there is Montenegro and Montenegrins," Mr Markovic said. "This day will be marked among the brightest in our history."

Opposition leaders said they do not recognise the parliamentary ratification and will call a referendum if they come to power in the future.

The country of 620,000 has been historically divided between pursuing pro-Western policies and sticking to an alliance with Orthodox Christian allies Serbia and Russia.

Russia and the pro-Russian opposition in Montenegro have also evoked the Nato bombing of Yugoslavia in 1999 - which included Serbia and Montenegro at the time - as a reason to stay out of the alliance.

Mr Markovic said Montenegro was drawn into Serbia's war with Nato and that membership in the alliance would help prevent anything like that from happening again.

"Nato and the EU have always been and remain a guarantee of stability and security and co-operation as the main basis for peace in Europe," he said. "It is about what kind of future we choose for us and generations to come."

Montenegro was formally invited to join Nato in December 2015. Mr Markovic said 27 out of 28 member states have ratified Montenegro's entry protocol and Spain would do so in the coming weeks.

Montenegro gained independence from Serbia in 2006.

AP