SKOPJE, Macedonia – Celebrations have begun in Macedonia to mark 100 years of independence in neighboring Albania, triggering an angry reaction from the country’s main opposition party and even political allies of the conservative government who warned that the anniversary events could stoke ethnic tension in the small Balkan nation.

The four-day anniversary celebrations will be launched in Macedonia’s capital, Skopje, on Sunday, and also include ceremonies later this week in the capitals of Kosovo and Albania.

Ethnic Albanians make up about 25 percent of Macedonia’s population of 2.1 million, but tension with the country’s Slavic-speaking Macedonian majority has remained high since a six-month armed ethnic Albanian insurgency in 2001 to demand greater autonomy in minority areas.

Thousands of Albanian national flags, a black double-headed eagle on a red background, are on display in parts of the capital and minority areas in the north and west of the country, on rooftops and public buildings.

The opposition Social Democrats described a decision by the government to join Albania’s independence celebrations as a “political provocation.”

Conservative Prime Minister Nikola Gruevski is partnered with the country’s largest ethnic Albanian party, the DUI, in his coalition government.

“We ask whether Mr. Gruevski and (DUI leader Ali) Ahmeti are aware that their irresponsible behavior and harmful policies will cause fresh ethnic tension and undermine the rule of law?” The deputy Social Democrat leader Gordan Georgiev said before the weekend celebrations.

Gruevski allies backing his government have also publicly argued that the Albanian celebrations are part of a minority drive toward creating a federal state – a notion dismissed by DUI leader Ahmeti.

Relations between the two main coalition partners have, however, soured in recent weeks after the country’s ethnic Albanian defense minister paid tribute to 2001 rebel fighters.

Gruevski responded by presenting draft legislation to grant pensions to former government soldiers who fought in the ethnic conflict – but not to rebel veterans.