The joint force entered the Iraqi National Congress (INC) building in southern Baghdad at 0545 GMT on Thursday, and removed documents, Chalabi's personal files, computers and personal belongings, said a security chief at the building.
"They took some personal documents, as well as files, party files and weapons, but they didn't arrest anyone," the chief said, declining to give his name.
Chalabi was not in the building - the headquarters of his INC group and where he sometimes sleeps - at the time of the raid, the source added.
An AFP photographer said Chalabi's bedroom had been turned upside down, cupboards left bare and framed portraits of the INC leader smashed.
A US military spokeswoman referred all inquries about the incident to the Iraqi interior ministry and was unable to confirm that American troops took part in the raid.
Chalabi told the US there were
WMDs in Iraq
But six Humvees and an armoured vehicle were still parked at the road early on Thursday afternoon.
Chalabi, a secular Shia, has recently courted disapproval from Washington amid claims his INC party fed false information to the US government and media before the 2003 invasion of Iraq.
US Deputy Defense Secretary Paul Wolfowitz said on Wednesday that the Pentagon had halted its monthly payments of $340,000 to Chalabi's party and would seek other intelligence sources on Iraq.
Chalabi has long been viewed with distrust by the Central Intelligence Agency and the State Department, but was closely aligned with hawks in the Pentagon, which flew him and INC militiamen into southern Iraq shortly after the invasion.
The INC has been providing information to the CIA-led group hunting for Iraq's alleged weapons of mass destruction as well as other intelligence to help protect US troops.