The Democratic Republic of Congo on Wednesday threatened to take international action over Angola's recent, and allegedly violent, expulsion of some 200,000 illegal migrants from its west African neighbour.
DR Congo invites the Angolan government "to carry out a thorough investigation in order to establish who was responsible for these reprehensible acts," Foreign Minister Leonard She Okitundu told a press conference in the capital Kinshasa.
Unless this is done, the DR Congo government "would be obliged to take the matter to the relevant authorities," he warned, adding that his country will not stoop to "brutally expelling" Angolans in any tit-for-tat response.
Since the start of the month Angola has expelled around 200,000 Congolese living clandestinely in its northern province of Lunda Norte, which borders DR Congo.
Angolan police said last week that they had targeted foreign nationals suspected of diamond smuggling.
Some 30,000 of these were "brutally" kicked out of the country, and some were killed, according to a report by the DR Congo cabinet chaired by President Joseph Kabila.
According to Angola, the 200,000 Congolese returned home voluntarily.
Kinshasa also accused the Angolan navy of violating the sovereignty of its territorial waters.
Angola and the Democratic Republic of Congo share a 2,500-kilometre (1,550-mile) land border, the longest in Africa.