"Over 105,000 people have now fled the country to neighboring Tanzania, Rwanda and to the province of South Kivu in the Democratic Republic of the Congo," Karin de Gruijl said at a press briefing.
The latest numbers were revealed as local media cited a presidential spokesman as saying that Maj. Gen. Godefroid Niyombare, the man behind Wednesday's failed coup, has been arrested. Three other senior army and police officers associated with the plot have also been detained.
"While the coup attempt is reported to have been foiled, the situation in Burundi's capital Bujumbura remains tense with sporadic outbursts of violence," de Gruijl continued at the briefing.
Niyombare was dismissed as the country's intelligence chief last February. The senior army official announced the overthrow of the government while President Pierre Nkurunziza was in Tanzania to attend a regional summit, spurring mixed reactions and violence in the streets of the capital, Bujumbura.
On Thursday, Nkurunziza announced his return to Burundi and appeared to have quelled tensions, saying the government had the situation under control.
The coup attempt took place in the wake of violent protests that erupted on April 26 over Nkurunziza's decision to run for a third term in office, deemed unconstitutional by critics. The president's supporters argue that he has a right to take part in the upcoming elections since he was appointment by the country's Parliament for his first term and not by a direct vote.