(06-21) 11:04 PDT SAN FRANCISCO -- The Obama administration announced plans Friday to protect crime victims and witnesses from deportation under a hotly debated program that requires local jails across the country to forward arrestees' fingerprints to immigration authorities.

While defending the program known as Secure Communities, U.S. Immigration and Customs Enforcement said it is making "key improvements" to further its stated goal of detecting and removing the most dangerous illegal immigrants.

"We need to do a better job of ensuring that the program is more focused on targeting those that pose the biggest risk to communities," said ICE's director, John Morton - who insisted that the agency has already taken large strides toward that goal.

One new measure appears to be designed to counter complaints from law enforcement agencies that the program discourages many victims and witnesses from contacting police for fear of being deported.

ICE said it would instruct its officers to "exercise appropriate discretion" to avoid such deportations, especially for victims of domestic violence, who sometimes are swept up by police along with their abusers. Morton said the agency would also provide civil rights training for police and establish an advisory committee, including police and immigrant advocates, to suggest further improvements.

But the announcement drew responses ranging from derision to anger among the program's critics, including a Bay Area legislator who has proposed allowing California counties to opt out of enforcement.

The changes are "simply window dressing," said Assemblyman Tom Ammiano, D-San Francisco. "How many more innocent people have to be swept up by the ironically named Secure Communities program before the Obama administration will change course?"

A coalition of California immigrants'-rights organizations, including the Asian Law Caucus, the National Day Laborer Organizing Network and the American Civil Liberties Union, called for "a national moratorium on this fundamentally flawed program."

Mandatory program

The program requires jails to forward to federal authorities the fingerprints of everyone they take into custody, to be checked against immigration records. A product of government policy rather than congressional action, it began in 2008 with voluntary state participation - California signed up early, in 2009 - and is scheduled to become mandatory in 2013.

So far, Morton said, of the 110,000 people deported under Secure Communities, more than 70 percent have had criminal records, and many of the others had been deported in the past or were being sought on immigration warrants.

"We do prioritize with a heavy focus on serious offenders first," Morton said. "This is a good program - smart, effective immigration enforcement."

Opponents put a different cast on the figures: Nearly half of those placed in deportation proceedings had either a minor criminal record or none at all. They say serious offenders can be located and deported under other programs, eliminating any need for a dragnet like Secure Communities.

San Francisco Sheriff Michael Hennessey, who opposes the program, is turning illegal immigrants over to federal immigration authorities only if they have been booked on serious charges or have extensive criminal records.

States want out

Citing some Obama administration statements that suggested the program would remain voluntary, the governors of Illinois, New York and Massachusetts have announced their states' intentions to withdraw. ICE has rebuffed them, saying Secure Communities is a nationwide program that all states must join.

Ammiano, author of California's opt-out legislation, said Friday he was undeterred. His AB1081, which has won approval from the Assembly and its first state Senate committee, would exclude counties from the program unless they chose to join, would exclude information about juveniles and would allow forwarding of fingerprints only after a criminal conviction.

Ammiano said he is uncertain about the bill's prospects with Gov. Jerry Brown, who as attorney general signed California's 2009 compact with ICE and refused to let San Francisco and other counties opt out. But if Brown signs the measure, Ammiano said he's hopeful that the Obama administration's opposition will yield to a court challenge or to public pressure.

"Without us standing up," he said, "it will continue."

This story has been corrected since it appeared in print.