The EU is preparing to pledge a 2025 deadline for the next wave of enlargement, but Balkans disputes could hold things back.

"The Western Balkans partners now have a historic window of opportunity. For the first time, their accession perspective has a best-case timeframe," the commission is to say in a strategy paper to be adopted either on 7 or 14 February.

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Zaev (l) said name dispute could be solved by July (Photo: ec.europa.eu)

"With strong political will, the delivery of real reforms, and lasting solutions to disputes with neighbours, Montenegro and Serbia should be ready for membership by 2025," the text is to add, according to a draft seen by EUobserver.

It aims to say Albania, Bosnia, Macedonia, and Kosovo "should also be well advanced on their European path by then", or, according to alternative words in brackets, that their "negotiations … should be well advanced."

The paper marks a shift in tone after commission head Jean-Claude Juncker said in 2014 there would be no EU enlargement in the foreseeable future.

Serbia and Montenegro have already opened accession talks.

Albania and Macedonia are hoping to do it this year, if Macedonia can resolve its name dispute with Greece.

Bosnia is angling to gain EU "candidate" status, while Kosovo is preparing to formally ask to become a candidate.

The commission paper warned that local disputes could hold back what it called its "ambitious" timeline.

"The EU cannot and will not import bilateral disputes. This is why all the Western Balkans partners concerned must resolve such disputes as a matter of urgency," the draft said.

It proposed that border issues should be solved by international arbitration, for instance in The Hague, and that rulings must be "binding, final" and "fully respected".

Thorny bramble

The thorniest dispute is Serbia's non-recognition of Kosovo's independence.

The commission paper said, nodding to Belgrade, that "frontrunners on the EU path have a strategic interest" in advocating the EU "aspirations of their partners".

It added that a "comprehensive normalisation of relations between Serbia and Kosovo in the form of a legally-binding agreement" was "crucial" for both their EU prospects.

Kosovo's problems go beyond Serbia, however.

Five EU states also do not recognise its independence.

Meanwhile, its new leader, Ramush Haradinaj, has vowed to block an EU tribunal in The Hague on Kosovo guerrilla war crime allegations.

The US, on Monday, refused to grant him a visa to attend an event in Iowa on 11 February in what looked like punishment.

A Serb general said the same day that Nato had "specific" information on a "security threat" in Kosovo due to the court row.

Name calling

The Macedonia-Greece name dispute could be resolved by July.

Greece has blocked Macedonia's EU and Nato entry talks for a decade on grounds that Macedonia's name implied a claim to a Greek region of the same name.

But Skopje and Athens say they are close to reaching a UN-mediated deal.

"We have a window for a solution," Greek prime minister Alexis Tsipras said on Monday after holding talks with Macedonian leader Zoran Zaev.

Zaev said: "I believe there's a chance by the end of the middle of 2018 to find a settlement."

The Greek foreign minister said Macedonia should adopt a composite name with a geographical qualifier. Zaev declined to comment, saying: "I don't want to ruin the procedure of the imminent negotiations".

Laundry list

The list of Balkans disputes goes on 20 years after the wars there ended.

Croatia and Slovenia, which are already EU members, cannot agree on their maritime border in what Juncker said on Monday could hold back wider enlargement.

Croatia also has open border issues with Bosnia, Montenegro, and Serbia.

Kosovo had agreed on its border with Montenegro, but Pristina is now refusing to honour the accord.

Juncker's Balkans agenda is taking shape under Bulgaria's six-month EU presidency, which started on 1 January.

The EU will hold a Western Balkans summit on 18 May in Sofia - the 15th anniversary of a previous one in Thessaloniki, Greece, when member states first promised to take in the region.

The commission also aims to publish its regular progress reports on the Balkans aspirants in April.

"We will decide … in the next eight, nine months how to proceed with each and every one of these countries," Juncker's spokesman said on Monday.

Turkey is the only other country with an EU perspective.

The Western Balkans paper seen by EUobserver did not mention it, but the commission will take stock of relations with Ankara in April.

Russian spoiler

Juncker's plans are also taking shape in the context of heightened Russian activity.

Russia is flooding Balkans media with anti-EU propaganda and stoking Serb nationalism with arms deals.

Last year, suspected Russian spies were behind a failed coup in Montenegro designed to stop it from joining Nato. The Albanian foreign minister, Ditmir Bushati, recently told EUobserver he also expected dirty tricks on the name deal in Macedonia this year.

"This is a possible scenario," Bushati said.