Two rebels and 17 Angolan soldiers were killed in two incidents in the oil-producing province of Cabinda at the weekend, the separatist Front for the Liberation of the Enclave of Cabinda (FLEC) said on Monday.
Authorities in the southern African, currently Africa's biggest oil producer, declined to comment. On Friday the government also did not respond to a FLEC claim that nine Angolan soldiers had been killed in the region.
Luanda rarely responds to such claims in a region where separatists have been waging a low-intensity guerrilla campaign for several decades.
The latest clashes broke out on Saturday and Sunday near the border with the Democratic Republic of Congo, FLEC said in a statement.
FLEC, which wants independence for a territory that accounts for half of Angola's oil output, has been more vocal since the death this year of its 88-year-old founder, Nzita Tiago, in exile in France.
Men claiming to be rebels boarded an offshore Chevron gas platform in late May and threatened foreign petroleum workers in a rare sign of the simmering instability in heavily guarded Cabinda.
The incident cast doubt on Luanda's assertion that FLEC has fizzled out since a 2007 peace deal. Analysts say the group does not have the ability to affect oil output in Angola, nearly all of which is offshore.