BELLINGHAM, Wash. -- The secretary of Homeland Security has ordered of a review of an immigration raid in Bellingham in which a third of the employees of an engine manufacturing shop were arrested.

Janet Napolitano said she wants to know why Tuesday's raid took place and said immigration enforcement should be focused on employers who hire illegal immigrants.

More than 70 immigration agents swarmed into Yamoto Engine Specialists Tuesday. With a federal helicopter flying overhead, 28 people, mostly Mexican nationals, were arrested, accused of being in the U.S. illegally and using phony Social Security numbers or fake identification papers to get their jobs.

On Wednesday, advocacy groups condemned the raid, saying the use of force was inappropriate, unnecessary and a waste of tax dollars.

Yamoto administrator Shirin Dhanani Makalai said Immigration and Customs Enforcement had raised questions five months ago about the legal status of some employees at Yamoto. She said her company was cooperating with that investigation, and that it never knowingly hired illegal immigrants. But employees were hauled away in handcuffs.

"Attacking workers, taking away the primary breadwinner, destroying a local business and leaving families torn apart is simply un-American and unjust," said immigration advocate Pramila Jayapal with OneAmerica.

Groups called for a moratorium on raids and changes in immigration law, which would allow thousands of undocumented workers already in the U.S. to stay in the country legally.

Of the 28 arrested Tuesday, three women were released for humanitarian reasons.

The others are being held in Tacoma while they wait to find out whether they'll be deported.