VIOLENT clashes have erupted across Burundi before a controversial referendum to extend President Pierre Nkurunziza’s term of office.

Proposed reforms to Burundi’s constitution would extend the presidential term from five years to seven, allowing Mr Nkurunziza to run again in 2020. 

While it would limit the president to two consecutive terms, it would not take into account previous time in office, paving the way for Mr Nkurunziza to stay in power until 2034.

Human rights groups have warned that the referendum would not be taking place in a free and fair climate because of a severe clampdown on political opposition.

Dozens of opposition activists have been arrested for promoting a no vote in the referendum, with official campaigning due to start today.

A government official was sentenced to three years in jail on Monday after threatening to push opponents of the constitutional reforms into a lake.

Melchiade Nzopfabarushe was detained after he told a rally near Burundi’s capital Bujumbura: “We said that we have ordered boats. We will send them (opponents) into Lake Tanganyika.” 

 The government rejected the comments and said it opposed “any subversive message which may jeopardise unity and cohesion among the Burundian people.”

Mr Nkurunziza came to power after a peace treaty was signed in 2005 bringing to an end a decade of conflict between the Tutsi-dominated army and Hutu rebels in which 300,000 people were killed.

He won a third term in 2015, which opponents claimed was a breach of the peace agreement.

Violent clashes followed, resulting in hundreds of deaths and 430,000 people forced to flee the country.