“We expect all political parties in Montenegro to work constructively within Montenegrin institutions and undertake measures which increase public trust in them,” Petar Stano, spokesperson for the EU Enlargement Commissioner, said on Wednesday.

He said the EU had considered the conclusions of international observers from OSCE’s Office for Democratic Institutions and Human Rights, OSCE/ODIHR, which were that the election was “professionally and efficiently run”.

But he noted that the EU shared the observation of the OSCE/ODIHR that “mistrust in public institutions and the judiciary diminished public confidence in the electoral process”.

In a statement on Monday, OSCE/ODIHR experts recommended taking measures to enhance confidence in Montenegrin public institutions and improve the election process.

Stano said Montenegro should follow the OSCE/ODIHR recommendations, emphasizing that the European Commission is aware that the preliminary results issued by the State Electoral Commission, DIK, on Monday, still await confirmation.

Preliminary results suggested that Filip Vujanovic, current head of state and candidate of the governing Democratic Party of Socialists, DPS, had won a third term by a tight margin.

The opposition maintains that its own candidate, the former diplomat Miodrag Lekic, won instead.

“Our people are checking the election materials. We are boycotting parliament. There will be protests,” Nebojsa Medojevic, from the opposition Democratic Front, largest opposition formation led by Lekic, said on Tuesday.

His group and another opposition party, Positive Montenegro, have decided to boycott the work of parliament until the final election results are determined.

The election commission said Vujanovic had won 51.21 per cent of the votes, while Lekic, who ran as an independent although he leads the largest opposition group, the Democratic Front, won 48.79 per cent.

Soon after the issue of the preliminary results, Goran Danilovic, head of Lekic’s campaign headquarters, said that they would not permit electoral theft.

With both candidates supporting EU membership for Montenegro, the campaign mainly focused on mutual accusations traded between Vujanovic and Lekic.

Vujanovic fought on the government’s record while Lekic accused him of not doing enough to tackle such serious problems as organised crime and corruption.