US troops have detained three militants with ties to fugitive Izzat Ibrahim al-Douri, a former top aide to toppled Iraqi leader Saddam Hussein.
Douri, who has a $10 million bounty on his head, is number six on the list of 55 Iraqis most wanted by the United States.
He is believed to play a role directing the insurgents and is one of the top former Iraqi officials still wanted.
The US military has been trying to determine possible links between Saddam loyalists and Muslim militants who may have crossed Iraq's border to wage a holy war against the US-led occupation.
A US military spokesman said raids after Saddam's capture were yielding valuable intelligance that would make it easier to make further arrests of guerrillas, who have killed 202 US troops since Washington declared major combat over on May 1st.