Two Kurds have been stabbed to death and an Arab killed in clashes with police in the Iraqi oil town of Kirkuk.
Tension followed pro-federalist rallies last week
The incidents happened a day after three people were killed and up to 30 injured during clashes between Kurds and Arab and Turkmen demonstrators.
Kirkuk police chief Turhan Yussef said the two Kurdish men were stabbed and their bodies thrown near a bridge.
A Sunni Arab man was reportedly killed as police tried to stop Arabs and Turkmen attacking Kurdish targets.
Ethnic tensions between Kurds, Arabs and Turkmen have been simmering in the oil-rich city since the fall of Saddam Hussein's regime in April.
"Unknown attackers stabbed two Kurds to death and threw their bodies near a bridge in the centre of the city," said Kirkuk police chief Turhan Yussef.
His deputy, Sirzad Rifaat Kader, said an Arab man was killed and two others injured by security forces in the south of the city where armed Arabs and Turkmen were trying to attack Kurdish targets.
Thousands of Turkmen and Sunni Arabs staged a protest on Wednesday at the Kurdish majority's attempts to incorporate Kirkuk into an autonomous Kurdish region within a federal Iraq.
Several thousand protesters marched on the Patriotic Union of Kurdistan HQ, chanting: "No to federalism, Kirkuk is Iraqi".
At least three people were shot dead and up to 30 injured as the demonstration turned violent.
Police said Kurdish peshmerga militiamen were responsible for the shootings, but some witnesses blamed the police themselves.
Kirkuk, with its mix of Kurdish, Arab and Turkmen residents, has previously avoided serious confrontation.
It has a council representing all of the city's communities, with a Kurdish mayor and Arab deputy.
Last week, thousands of Kurds took to the streets to lay claim to the area - a major oil centre where the old Baath regime of Saddam Hussein settled large numbers of Arabs from the 1970s.