WASHINGTON — Since the Bush administration rolled out a program in 2008 that shares fingerprints between local police and federal immigration agents, about 30,000 illegal immigrants convicted of serious crimes have been deported.

But even more immigrants — roughly 33,000 — have been thrown out of America without ever being convicted of non-immigration crimes.

Opponents of the program, Secure Communities, say it casts too wide a net and threatens community policing. The governors of Massachusetts, New York and Illinois have joined them in recent months.

While immigration officials defend Secure Communities and their plans to expand it to the entire country, they acknowledged the growing criticism again last week by giving a task force more time to look into the program.

For years now, illegal immigration has been a hot-button issue. It's prompted new laws, tough enforcement, political action and localized violence. Some charge that illegal immigrants are stealing American jobs. Other see their labor as helping the nation keep its competitive edge at a low cost and filling jobs that many citizens refuse to do.

In June, the director of Immigration and Customs Enforcement, John Morton, announced that the agency was creating an advisory committee to look into the program's practices relating to minor traffic offenses and report in 45 days, he said.

Immigrant-rights groups remained skeptical, and on Wednesday more than 200 of them sent Morton a letter criticizing the committee's scope and composition.

"To adequately examine the program," they wrote, "the committee, at a minimum, must include affected community members who can speak to the impact of the program and be allowed to do significantly more than simply make recommendations about minor traffic offenses."

A spokeswoman for ICE, Nicole Navas, told McClatchy Newspapers on Friday that the agency has given the task force more time to report its findings. The committee requested the additional time to solicit feedback from the public, law enforcement and other stakeholders, she wrote in an email.

The committee now will issue its final report in September, according to its chairman, Chuck Wexler, the executive director of the Police Executive Research Forum.

During the Obama administration — which deports more immigrants than any other in American history — and the Bush administration, Secure Communities has produced only a small portion of ICE's deportations.

The record numbers are concerning to Sarnata Reynolds, the policy director for refugee and migrant rights at Amnesty International USA. Reynolds said most of the immigrants who were being deported were contributing members of society, and that many were doing jobs that employers couldn't find enough Americans to do.

"Crossing the border doesn't mean that you don't have human rights," Reynolds said. "It doesn't mean that you don't have civil rights."

Although Secure Communities is only one component of ICE's enforcement efforts, immigrant-rights groups see it as particularly disruptive.

"I think it deservingly has gotten the most attention," said Melissa Keaney, a lawyer with the National Immigration Law Center, one of the groups that signed Wednesday's letter.

The program works by comparing the fingerprints taken in participating police stations against a nation database of immigration offenders. All the immigrants booked into the system have been arrested, but the matching process can take place before a decision is made about whether to charge them with crimes.

In April the Los Angeles Times published the story of an undocumented woman who, through Secure Communities, was turned over to immigration authorities after she called police to report domestic abuse. Police had booked her after seeing a red mark on the cheek of her alleged abuser, but she was never charged with a crime.

Stories such as that are making illegal immigrants less likely to cooperate with police, Reynolds said.

"The program has been touted as this unique and narrow tool that will target the worst of the worst," Reynolds said. "But instead, what it's done is sown incredible fear."

Secure Communities' effects on community policing have been discussed frequently by opponents to the program. Earlier this month, citing similar concerns, Boston Mayor Thomas Menino threatened in a letter to ICE director Morton to drop the program if it weren't improved.

As Wednesday's letter shows, many opponents think that ICE's task force stands little chance of significantly changing the program.

"I'm not optimistic," said Jacqueline Esposito, the director of immigration advocacy at the New York Immigration Coalition. "It's clear that (creating the task force) was a political move by ICE. It was not a genuine attempt at policy reform."

Navas, the ICE spokeswoman, disagreed, saying in her email that the committee shows the administration's "commitment to smart, effective immigration enforcement."

On the day last month that Morton announced the formation of the task force, he also issued a memorandum on "prosecutorial discretion," the power that ICE agents have to decide what action to take with suspected illegal immigrants. The memorandum asked agents to consider a list of factors, such as whether the person arrived as a child or served in the military, before deciding to pursue deportation.

Navas called last month's changes, including the creation of the task force, "key improvements" to Secure Communities. ICE plans to expand the program, which is now functioning in about half the jurisdictions in the country, to every jurisdiction by 2013.