Twenty-four people have been arrested in Burundi as part of a security crackdown on "homosexual practices", a judicial source and an activist told AFP on Friday.

The arrests took place on February 23 in the political capital Gitega, where members of MUCO Burundi, a non-profit organisation that focuses on HIV/AIDS, were attending a seminar, an activist told AFP on condition of anonymity, citing fear of reprisals.

"They are accused of homosexual practices and of inciting homosexual practices among adolescent boys and girls to whom they give money", the activist said, calling the claims "absurd and baseless".

"There is not a shred of evidence for these serious accusations."

The governor of Gitega province, Venant Manirambona, confirmed the arrests to AFP but refused to elaborate further.

"Yes, these people were arrested, but I cannot comment on a case that is still under judicial investigation," he said on Friday.

A judicial source told AFP that neighbours had alerted security officials when they saw "adolescent boys and girls" at the MUCO office.

Police then "found condoms and documents on the rights of homosexuals at the scene", the source said, adding that the 24 were arrested on suspicion of engaging in "homosexual practices and incitement to homosexual practices".

Burundi has criminalised homosexuality since 2009 with a prison sentence of up to two years for consensual same-sex acts.

On Wednesday, President Evariste Ndayishimiye urged citizens to root out homosexuality from the country.

"I ask all Burundians to curse those who indulge in homosexuality because God cannot bear it," he said in a speech.

"They must be banished, treated as pariahs in our country", he said.

Last month Burundian intelligence agents arrested five human rights activists, who were later charged with rebellion and undermining state security.

In January, Burundian journalist Floriane Irangabiye was sentenced to 10 years in prison on charges of "undermining the integrity of the national territory".

Despite ongoing concerns about the rights situation, both the European Union and the United States last year resumed aid flows to the deeply impoverished landlocked nation, citing political progress under Ndayishimiye.

Burundi had been under US and EU sanctions over a bloody crisis that erupted in 2015 when former president Pierre Nkurunziza made a controversial bid for a third term in office.

The turmoil claimed the lives of 1,200 Burundians and saw 400,000 flee the country.