Luanda (AFP) - Separatist guerrillas operating in Angola's oil-rich Cabinda enclave on Wednesday claimed to have shot dead around 30 Angolan government soldiers in March.
Angolan authorities refused to comment on the claims which AFP could not independently verify.
The Front for the Liberation of the Enclave of Cabinda (FLEC) has been fighting for the independence of Cabinda for four decades.
In a statement received by AFP the FLEC said it staged an attack on March 13 which resulted in "several serious injuries... and more than 10 deaths" among the Angolan army soldiers.
A second ambush on March 16 killed 20 troops in the town of Buco-Zau.
FLEC urged "Western nationals living in Cabinda to temporarily leave."
"We are in a state of war and we face a massive military invasion from Angola," FLEC said.
Speaking on condition of anonymity, a senior government source said the defence minister had visited the enclave in February while the army commander went there earlier this month.
"All this shows that the situation in Cabinda is worrying," the source told AFP.
Neither the source nor officials contacted by AFP could confirm or deny FLEC's claims on the deaths of the troops.
Alexander Kuanga, a civil society activist in Cabinda, confirmed that the military had increased its presence in the province.
"The situation is normal in the provincial capital, (but) troubles occur in the bush," he said, adding the "population is scared to go to the fields to cultivate."
With a population of 400,000 people, Angola's Cabinda province is an enclave that borders on Congo to the north, while being separated from the rest of Angola to the south by a sliver of territory belonging to the Democratic Republic of Congo.
Though small, Cabinda accounts for much of Angola's oil production, which makes the country the second largest exporter in Africa.
Despite a peace deal in 2006, FLEC factions continue to wage low-level attacks in the province since independence in 1975.
FLEC's last major attack was staged in January 2010, when a bus carrying Togo's football team was ambushed as it entered Angola for the African Cup of Nations. Two people were killed and one person seriously injured.