It brings to 16 out of 35 the number of sections now open and confirms Podgorice’s lead position in terms of EU and Nato membership prospects.

It comes one day after EU foreign ministers allowed Bosnia more flexibility on constitutional reform in its bid to complete a Stabilisation and Association Agreement, a pre-accession treaty.

The European Commission in October recommended opening two new chapters with Turkey, while staying silent on Montenegro.

But Russia’s increasing influence in former Yugoslavia has caused alarm in EU capitals.

Sandro Gozi, Italy’s EU affairs minister, said the Montenegro decision “was not in any way affected by external relations”.

But Montenegro’s foreign minister, Igor Luksic, noted that, unlike Serbia and Turkey, Montenegro has aligned itself with EU sanctions on Russia despite a "centuries-old tradition" of friendly ties.

“It was a difficult call. But it was also very clear we cannot at the same time be on two sides, we cannot straddle, sit on both chairs at the same time, as our strategic choice is to join the EU".

"It’s always been the only reasonable choice”.

The EU Council’s annual stock-taking of enlargement developments was this week all-but hijacked by a row on Turkey’s mass arrest of opposition journalists.

The EU ministers’ conclusions on Tuesday said Turkey is still on the path to accession and is a “key partner” on energy, trade, and the Iraq-Syria crisis.

But they said nothing on opening new chapters.

They also said its crackdown on press, judges, and police who tried to investigate high-level corruption “cast[s] serious doubts over the independence and impartiality of the judiciary, and demonstrated an increasing intolerance of political opposition, public protest, and critical media”.

Italy’s Gozi said he was also “very surprised” that Turkey’s leader, Recep Tayyip Erdogan, on Monday told the EU to “mind its own business” on civil liberties.

He called press freedom “one of the fundamental issues for the European Union”.

He stopped short of asking Turkey to release the detained reporters. But he added: "We think this [the ministers' conclusions] is a very strong messages to the authorities in Ankara".

The conclusions on Albania, Kosovo, Macedonia, and Serbia also underlined that - despite the Russia crisis - rule of law has “central importance” in the EU accession process.

They called on Albania to do more on organised crime.

They said on Macedonia “there are serious concerns about increasing politicisation of state institutions and growing shortcomings with regard to the independence of the judiciary and media freedoms”.

They tied the opening of Serbia accession chapters to progress on “normalisation” of relations with Kosovo and to Belgrade adopting EU sanctions on Russia.

The normalisation talks are to resume in Brussels in January after a pause for elections in Kosovo.

The EU on Tuesday instructed Kosovo’s new government to adopt laws, “as a matter of priority”, to enable it to set up a Kosovo war crimes tribunal in The Hague.

The tribunal is to start work in early 2015.

It could end up indicting former commanders in the Kosovo guerrilla army, the KLA, including Kosovo’s former PM, now foreign minister, Hashim Thaci, who was named in a 2010 Council of Europe report on organ trafficking.