The fires came after more than 50 people were killed on Monday in clashes between protesters and security forces in Kinshasa
The headquarters of three DR Congo opposition parties were torched overnight and early Tuesday, a day after deadly clashes between police and opponents of President Joseph Kabila, AFP journalists said.
At least two burnt bodies could be seen in the fire-ravaged offices of the main opposition Union for Democracy and Social Progress (UDPS), while two other people were burnt alive and one person injured, they said.
By 8:30 am (0730 GMT) flames were dying down at the headquarters of the Forces of Union and Solidarity (FONUS) and the Lumumbist Progressive Movement (MLP) in the north of the capital Kinshasa.
The fires came after more than 50 people were killed on Monday in clashes between protesters and security forces in Kinshasa, according to opposition groups.
Opposition leaders are calling for the resignation of Kabila, who has ruled the Democratic Republic of Congo since 2001, saying he is planning to extend his rule unconstitutionally.
The clashes Monday were the worst violence in the capital since January 2015 when a police crackdown on another opposition protest left several dozen people dead.
Although Kabila is banned by the constitution from running again, he has not made any move to schedule elections, fuelling fears he will seek to extend his stay in office.
In May, the Constitutional Court said Kabila could remain in office in a caretaker capacity until an election is held, triggering a wave of angry protests.