IOWA CITY (AP) - Immigration officials have detained 20 people following a traffic stop on Interstate 80 in eastern Iowa.

A Coralville police officer stopped a van Thursday morning for speeding on I-80 in Iowa City. Police say the officer became suspicious after questioning the driver and because the van's windows were blacked out.

The driver eventually admitted that 11 people were in the back of the van, but police say the officer found 20 people when he ordered them out of the van.

Police say the officer was suspicious about the immigration status of the van's occupants and notified officials from Immigration and Customs Enforcement.