After he won a disputed third term, diplomatic sources said Tuesday.
The sources told AFP that the European Union had agreed in principle to hit the four with travel bans and asset freezes, with a formal decision due Thursday.
Nkurunziza himself was not being targeted however “because Europe wants to give dialogue a chance with him,” one of the sources told AFP.
Nkurunziza won a controversial third five-year term in July in polls boycotted by the opposition as unconstitutional for breaking a two-term limit.
His re-election sparked an attempted coup by rebel generals and months of civil unrest in the small, impoverished central African country.
Brussels warned at the time it would review cooperation with Burundi, including crucial trade and development links.
It also warned that sanctions could follow against those found responsible for “acts of violence and repression.”
A 1993-2006 civil war claimed at least 300,000 lives in Burundi.