In the raid on the Kurdish parties' offices, US troops seized AK-47 rifles and rocket-propelled grenades.
One senior member of the Kurdistan Democratic Party (KDP) was taken into custody after the raids on Saturday night, Sergeant Robert Cargie of the 4th Infantry Division said.
A KDP office and an adjacent office of the Patriotic Union of Kurdistan - the two key parties representing the Kurdish minority in Iraq - were both raided, he said.
Tension surfaced on Wednesday in Kirkuk, 250km north of Baghdad, after Arab and Turkish-speaking Turkmen residents marched on the headquarters of a Kurdish party to protest a Kurdish political push for more control in the area.
At least six people have since been killed in ethnic clashes, though tension seemed to abate after US troops imposed a night curfew on Saturday. Kirkuk sits on Iraq's richest oil reserves.
Iraqi policemen injured
In the north of Baghdad, five Iraqi policemen were wounded after US soldiers fired back at insurgents who had ambushed them with a rocket-propelled grenade.
According to police Lieutenant Muhammad Ibrahim "five policemen were wounded by US fire and hospitalized" in Bohruz, just south of Baquba.
An RPG had been fired on a US patrol near Bohruz's police station at about 20:00 GMT on Saturday and the soldiers returned fire, he said.
The US military later confirmed five policemen were wounded on Saturday night in Baquba, 60 km northeast of Baghdad.
Clashes in Kirkuk have left six
But according to the US military, the incident happened at 16:30 GMT and occurred inside the city when insurgents ambushed US troops.
"In the ensuing crossfire, five policemen were wounded. Four of them suffered minor wounds," said Sergeant Robert Cargie.
The fifth was still in hospital, he added.
Baquba is located inside the Sunni triangle, north and west of Baghdad, home to many supporters of former dictator Saddam Hussein.
Iraqi women and child killed
On Saturday, four Iraqis, including two women and a child, were killed when a US convoy opened fire on a family car trying to overtake it in a northern Iraqi town.
Elsewhere, a soldier was killed and two injured in an attack on a US army base northwest of Baghdad, a military spokesman said on Saturday. The US military also confirmed two soldiers were killed by a bomb south of Baghdad on Friday.
The US military said it was looking into Saturday's shooting of civilians in Tikrit, but no immediate comment was available.