The leftwinger set to become Kosovo’s surprise new prime minister has condemned the EU’s decision to halt further Balkans enlargement, saying it showed western leaders had forgotten the lessons of two world wars and instead were in retreat in the face of fascism and populism.

Albin Kurti said the stance could damage the chances of Kovoso reaching a deal with Serbia, which has refused to recognise it as independent since the end of the 1998-99 war, as Belgrade has less incentive to act without the prospect of EU membership.

France caused dismay in the region at an EU summit last week by blocking Northern Macedonia and Albania from starting accession talks, so destroying Serbia’s chances of reaching the EU in the foreseeable future. French president Emmanuel Macron insisted that Europe needed to focus on its internal reforms.

“The EU was formed as a response to fascism, but is now running scared in the face of populists and fascism,” Kurti told the Guardian.

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Criticising Macron, he said: “You cannot say first we need internal reform in the EU and then external enlargement – they go hand in hand. Europe is such an important historical project that no one man can be its author, directing or leading it. We have always seen that when [the outgoing EU Commission president] Jean-Claude Juncker said there would be no further expansion in the next five years, the situation in the Balkans got much worse.

“Yes, the EU is important for the Balkans, but the Balkans is very important for the EU. Berlin and Paris should know this well, and it is really sad, for all of us, that they forget this. In a couple of decades, historians will write there were not two world wars, but just one world war with two episodes, and it all started in Sarajevo.”

Kurti’s leftist Albanian nationalist movement Vetëvendosje (Self-determination) emerged as the strongest party following snap elections last month. Imprisoned for 18 months by Serbian police during the height of its military conflict with Kosovo in 1999, Kurti, 44, finds himself on the verge of power, promising to end Kosovo’s two decades of neoliberalism.

He is currently in talks with the centre-right party LDK, which came second, on forming an administration, in which a minimum of 30% will be women. Kurti predicted an agreement within a month and says his priority is jobs and justice, not reaching a deal with Serbia.

After years of failed prosecutions against corruption, he promised to end what he considered the judiciary’s capture by the state.

He said he was interested in UK-style unexplained wealth orders and a new vetting process led by a dynamic chief prosecutor. “We need to produce our own homegrown Eliot Ness, and he must become the most famous person in the country,” he said. “We have almost 200 prosecutors, but some lack knowledge and some lack courage, and some lack both. They have to be liberated from the state.”

Facing mounting debt and emigration, Kurti said he was also determined to end the huge skills gap in the labour force, focus on technical education and reducing industry’s dependence on the crippling interest rates of foreign-owned banks: “We must make our country liveable and persuade more people to stay in our country.”

But Kurti will be under international pressure to reach an agreement with Serbia. The US has just appointed a new special envoy to revive the dialogue between the two countries..

He warned that the 100% import tariffs that his predecessor slapped on Serbian goods will be lifted only if there are full reciprocal measures on freeing Kosovo’s trade into Serbia. He said Belgrade also had to end its international diplomatic campaign to persuade countries to derecognise Kosovo. “If they want to start dialogue, they should explicitly stop the slander about our right to statehood,” he said.

Serbia, for instance, has opposed Kosovo’s membership of Interpol, Unesco and the Council of Europe. “Serbia should face its own past, instead of looking at Kosovo and Albania through military binoculars. Serbia needs some introspection.”

Kurti said his three-stage programme will start within a bottom-up dialogue with Serbs in Kosovo on practical cooperation, for example in agriculture, followed by a review of the real-life impact of the 33 agreements signed with Serbia under EU auspices from 2012, and finally a meeting with Josep Borrell, the incoming EU foreign policy chief. “We cannot afford another failed dialogue. It must have clear principles,” Kurti said. Borrell has promised to go to Kosovo as his first overseas visit.

Kurti said he was totally opposed to land swaps with Serbia, an idea pursued this year by Serbian president Aleksandar Vucic and Hashim Thaci, the president of Kosovo. “Whatever new border you form, there will be Serbs or Albanians on the other side, and they pretend you can do it peacefully.”

Serbs fear that his true agenda will be to seek some kind of confederation with Albania, so marginalising the Serb minority in northern Kosovo.

Serbia has already condemned as provocative his decision to meet foreign diplomats at his party headquarters with an Albanian flag behind him. He said Kosovo’s official flag was imposed on the country with a ruling that it contain no red, no black and no eagle, “as if we were declaring independence from Albania, and not Serbia”.

But he vowed in his official capacity as prime minister that he will retain and respect the official flag of Kosovo: “I have more important tasks than rearranging the furniture in the prime minister’s office.”