Angola has returned over 180 000 illegal migrants from the Democratic Republic of Congo back across the border since the start of a security crackdown last week, Angolan authorities said on Tuesday.
Police said they targeted foreign nationals suspected of diamond smuggling.
Angola's operations against the migrants triggered clashes between Congolese, security forces and local Angolans largely in the northern province of Lunda Norte, which borders on DRC.
Local media and an NGO reported that several migrants have been killed, though Angolan authorities deny any deaths.
"In recent days, at least 180 802 citizens of the DRC have freely left our country," police chief Antonio Bernardo told reporters on Tuesday.
Congolese border posts in the region confirmed that several thousand DRC citizens have returned in recent days.
Bernardo added that 800 foreigners from DRC, Lebanon, Mali and Nigeria had been arrested over involvement in the illegal diamond trade in the area.
He said 120 trading premises had been closed and 30 000 diamonds seized.