Votes are being counted after Albania's parliamentary election, with early returns showing the opposition Socialist-led alliance ahead.
Socialist leader Edi Rama and his main rival, Prime Minister Sali Berisha, both claimed victory on Sunday night.
Shots fired near a polling station killed an opposition activist and wounded a candidate for Mr Berisha's Democrats, in the northern town of Lac.
The official election results are not expected before Tuesday.
With about 10% of votes counted in most regions the left-wing alliance called Renaissance was several points ahead on Monday, Reuters news agency reported.
As head of the alliance Mr Rama, the former mayor of the capital Tirana, hopes to break Mr Berisha's domination of Albanian politics since the communist government was ousted in 1991.
The EU said Sunday's election "represents a crucial test for the country's democratic institutions and its progress towards the European Union".
Mr Berisha is seeking a third term, but the campaign was marred by allegations of vote-rigging, fuelling fears of political instability.
A dispute over the country's electoral commission also threatens to leave the result in doubt.
Results 'at risk'
Elections in Albania, one of Europe's poorest countries, have been marred by violence or claims of fraud since the fall of communism.
After polls closed Mr Berisha told reporters that he was "convinced of our great victory".
However, Mr Rama insisted "the Renaissance has won".
Both politicians promise job creation, economic development and tax reform.
They are also both strongly pro-European, reflecting widespread public support for EU integration.
About 400 international observers and more than 8,000 Albanian monitors were deployed for the polls.
Because of a dispute between the two rival coalitions, the seven-member Central Electoral Commission has only four members. The minimum legal requirement is five.
On Saturday, a Western diplomat told AFP news agency that there was now "a great risk the results [of Sunday's polls] would be contested, either by the outgoing coalition or by the opposition".
Sunday's shootout took place near a polling station in Lac.
A police spokesman said an activist from Mr Rama's party, Gjon Gjoni, was killed in an exchange of fire with Mhill Fufi, a candidate for the governing party.
Mr Fufi was seriously wounded and is reportedly being treated at a hospital in Tirana.
More than 6,900 candidates from 66 political parties contested 140 parliamentary seats.