WASHINGTON — Federal authorities arrested 582 alleged gang members over a two-week period, officials said yesterday, targeting an estimated 80 violent groups that they say have spawned street crimes across the country.

Homeland Security Secretary Michael Chertoff called the gangs "a threat to our homeland security and ... a very urgent law-enforcement priority."

Investigators picked up most of the alleged offenders between July 16 and 28 on suspicion of immigration violations. Seventy-six face criminal charges, ranging from illegal possession of a firearm to holding fraudulent documents.

Immigration and Customs Enforcement (ICE) agents targeted members in 27 states of what they considered to be the most violent street gangs, including Mara Salvatrucha, or MS-13; Latin Kings; and the Mexican Mafia. ICE is an arm of the Homeland Security Department.

Many of the arrests came in large urban areas, including 61 in Boston, 28 in Denver, and 23 each in Los Angeles and Detroit.

The crackdown is part of ICE's ongoing "Operation Community Shield" campaign, targeting gang activity with other federal and state authorities.

So far, ICE has made 1,057 arrests as part of the campaign.