Explosions and gunfire are reported in Burundi’s capital, Bujumbura, as polls open in a divisive presidential election.

Polling stations opened in Burundi on Tuesday for a controversial presidential election that was being boycotted by the opposition.

Some 3.8 million Burundians are eligible to vote.

The election, according to many in the African country, threatens to plunge Burundi into a deepening spiral of violence.

At least two people were killed -- one policeman and a civilian -- in a string of blasts and gunfire overnight on Monday, according to local reports.

At least three loud explosions and sustained bursts of gunfire were heard in the capital.

Witnesses told reporters that unknown assailants in the northern suburb of Ngagara city, located in the western part of the country, opened fire on police officers who fired back.

The president's office has described the latest incidents as terrorist acts intended to disrupt the election.

The opposition has called for a boycott of the election, which is going ahead despite months of violent anti-government protests and appeals from the international community for the incumbent leader to step aside.

The presidential election comes as the parliamentary and local elections on June 29 went ahead in the African country despite an international outcry.

The African nation plunged into political turmoil in late April, when President Pierre Nkurunziza announced his decision to run for a third consecutive five-year term in office.

The opposition says the 51-year-old's bid to extend his 10-year rules contravenes the constitution, which states a president can only serve two terms.

Over 80 people have been killed, hundreds wounded and more than 1,000 jailed in Burundi since late April. More than 500,000 people have also fled the violence to neighboring states.