"The 'insurrectional movement' has caused significant losses on all sides," said a report by Public Security Minister Alain Guillaume Bunyoni, who himself was slapped with sanctions last week by President Barack Obama, over his alleged links to the country's descent into violence.
Bunyoni, the regime's number two, said that 34 police officers were killed and 293 were injured in attacks by insurgents.
Burundi's government blames a string of attacks on "armed criminals", but the UN has warned that Burundi risks sliding back into civil war after a dramatic rise in violence.
In the report, Bunyoni says the police had handled the situation with "professionalism, loyalty and self-sacrifice."
Rights groups offer a different picture. Testimonies recorded by Amnesty International accuse both the police and National Intelligence Service (SNR) of "torture and other ill-treatment" against protestors.
Police beat people with electric cables and batons, while the SNR used iron bars, as well as "forcing detainees' heads under dirty water," Amnesty said in an August report.
The US action imposes visa restrictions on the four and blocks their US assets, a White House statement said, adding that it was considering similar action against other individuals.
"These sanctions are a fraud... I do not give a damn," Bunyoni said in reply on Monday.
President Pierre Nkurunziza, an ex-rebel turned born-again Christian who believes he has divine backing to rule, won a third term in power in July, despite concerns over the legality of him serving a third consecutive mandate.
