Thieves who steal the identities of others to forge credit cards, passports and other documents would face speedier prosecutions and tougher prison sentences under guidelines announced Thursday by federal officials.

Attorney General John Ashcroft said he has ordered federal prosecutors around the country to speed up investigations and trials of accused identity thieves, resulting in the prosecutions of 135 people over the past month.

The sweep coincides with legislation moving through Congress which would force judges to add time to sentences for crimes involving identity theft.

In a pairing of political figures who have been on opposite sides of many issues, Ashcroft and the bill's sponsor, Sen. Dianne Feinstein, D-Calif., told a news conference that the two-pronged approach was necessary to force local law enforcement to pay attention to identity theft, one of the nation's fastest-growing and most expensive crimes.

"This has been a crime that has not been taken terribly seriously until recently," Feinstein said. Though the Bush administration will not formally comment on the bill until next week, Ashcroft "adds clout" to the issue, she added.

Identity thieves use information from their targets, such as Social Security numbers, birth dates and addresses, to create or obtain phony documents like personal checks, credit cards and passports.

Ashcroft said as many as 700,000 Americans have their identities stolen each year. Other lawmakers have estimated that identity theft has victimized one in five families as well as thousands of credit card and other companies.

Identity theft was central to a millennium plot to blow up Los Angeles International Airport. Algerian Mohamed Amry stole the information of 21 people from the Cambridge, Mass., fitness club where he worked to create false green cards and Social Security cards, authorities have alleged. The fake IDs were used to open bank accounts, prosecutors said; allegedly, counterfeit checks were deposited into those accounts and money was withdrawn from them.

In addition to ordering stepped-up prosecutions, the Senate legislation would create a new crime of "aggravated identity theft," for which judges would have to add two years in prison to any sentence for a crime involving identity theft.

The additional penalty grows to five years for those convicted of using identity theft in plots of domestic terrorism.

The Federal Trade Commission maintains a database called the "Consumer Sentinel," which keeps track of fraud complaints. Last year, the database reported that identity theft was the subject of 42 percent of all complaints received, more than any other category of consumer fraud.