Burundi's ruling party says all citizens of its former colonial power, Belgium, should leave the country.
Belgium last week said those "whose presence is not essential" should leave because of increasing levels of violence.
Burundi has accused Belgium of links to opposition groups it blames for a spate of killings.
The unrest began in April when President Pierre Nkurunziza announced he would seek a third term.
Belgium said it had about 500 citizens in Burundi but Robert Misigaro, from the BBC's Great Lakes Service, says there have been no signs of mass evacuations at the airport.
He says the statement from the CNDD-FDD party is a further ratcheting up of tensions between the two countries.
In the statement the CNDD-FDD said Belgium's recent warning for its citizens to leave "shows that colonialist-Belgian politicians are ready to go to any length when it comes to issues regarding Burundi".
At least 240 people have been killed since April.
The violence has increased in recent weeks, with bodies found on the streets on a daily basis.
Last week, the UN Security Council unanimously adopted a resolution strongly condemning the escalating violence.
The French-drafted resolution also paves the way for a possible deployment of blue-helmeted UN peacekeepers.
Burundi's constitutional court backed Mr Nkurunziza's third-term bid, as his first term as president did not count towards the constitutional two-term limit because he was chosen by MPs, rather than in a popular election.
Mr Nkurunziza was duly re-elected with 70% of the vote in July.
Burundi: Key facts
The country is facing its worst turmoil since the 12-year civil war ended in 2005
