TIRANA, Albania (AP) — A shooting outside Albania's capital that reportedly was linked to political party activists before a parliamentary election this week killed one person and injured four others on Wednesday, according to police and media reports.

A police statement said that an officer was among the injured after she tried to break up an argument in the central city of Elbasan, 35 kilometers (20 miles) south of Tirana. Several people have been detained, including the suspected gunman. No further details were given by police.

Local media reported that the victim and one of the injured people worked at the governing Socialist Party's local office while the alleged attacker is a bodyguard of a center-right main opposition Democratic Party politician. Another two of the injured were allegedly bodyguards for the same Democratic Party politician.

Albanians will elect 140 lawmakers in a vote which is considered as key to convince the 27-nation European Union bloc to agree on starting full negotiations on potentially admitting the small Balkan nation as a member. Irregularities have marred previous elections in post-communist Albania.

Prime Minister Edi Rama, the leader of the governing Socialist Party, called for calm and patience, adding that Sunday's election will unite Albanians.

Taulant Balla, the head of the Socialists’ parliamentary group, accused the Democratic Party of sending “groups of paramilitaries, armed men from other cities” to intimidate voters in Elbasan.

Gazmend Bardhi of the Democratic Party, whose bodyguard reportedly opened fire, said a car allegedly belonging to the Socialists' group was distributing money among voters.

The U.S. Embassy and the EU office in Tirana made a call to the main political leaders in the country to “exercise restraint” and “to clearly reject violence” before the election.

The electoral campaign has been tense in the final days before Sunday’s election, in which pre-electoral polls indicate that the Socialists will get the most votes.

Supporters of the two main opposing political parties clashed before in Elbasan in February.

A few days earlier, a Democratic Party activist was injured in the western city of Kavaja, in an incident for which the Democrats blame the governing Socialists.

On Wednesday, Albania's president harshly criticized Rama in an interview with The Associated Press, claiming he runs a “kleptocratic regime.”