More than 179,000 illegal immigrants convicted of committing crimes, including violent ones, continue to roam free across the United States, with reports indicating that these illegal immigrants commit new crimes "every day," according to lawmakers and the director of the Immigration and Customs Enforcement agency, also known as ICE.

Sarah Saldana, ICE’s director, disclosed to Congress on Wednesday that the agency is apprehending and removing fewer illegal immigrants than in past years.

Somewhere around 179,029 "undocumented criminals with final orders of removal" from the United States currently remain at large across the country and are essentially untraceable, according to Sen. Chuck Grassley (R., Iowa), chairman of the Senate Judiciary Committee, who disclosed these numbers during a Wednesday hearing.

The total number of criminal illegal aliens in the United States is in the millions.

Illegal immigrant criminals are known to be committing new crimes "every day," according to Sen. Jeff Sessions (R., Ala.), another member of the committee.

Focus on the threat of criminal illegal aliens comes amid a wider national debate on immigration to the United States and the threat posed by potential terrorists and other criminals.

The Washington Free Beacon disclosed in August that the Obama administration had been keeping secret the release of violent criminal illegal immigrants and only began notifying local law enforcement agencies about this within the last several months.

The administration is continuing a policy of hiding information about this issue, as "several administration officials informed the committee they were unable to testify because the hearing wasn’t ‘in response to a particular crisis,’" Grassley said.

Saldana revealed at the hearing that somewhere between 30,000 and 40,000 illegal immigrants previously convicted of crimes have been released from custody in recent years due to legal restrictions on how long the agency can detain an individual.

"Whether it’s a result of protracted appeals or refusal of a country to accept its nationals back, this decision accounts for somewhere between 30,000 and 40,000 convicted criminal alien releases in recent years," Saldana said, noting that the number has dropped over time.

Lawmakers remain concerned that the Obama administration is dragging its feet when it comes to taking action to deport criminal illegal immigrants. While President Barack Obama has vowed that this would be a priority for his administration, these criminals continue to be released into the United States.

"Many criminals remain in our communities," Grassley said. "When will enough be enough? Even those with violent criminal histories aren’t being removed as promised … American citizens are paying the price while law enforcement officers are instructed to look the other way."

There have been "thousands of victims" of crimes committed by illegal immigrants and "many of the agency’s own officers are unable to do the job they signed up to do," he said.

The Obama administration is removing fewer total illegal immigrants from the United States than it was just a few years ago, according to Sessions.

"Not only are total removals down, but the number of removals of criminal aliens from the interior of United States, the so-called priority, has decreased significantly," he said. "The reason for this decrease is not because there are fewer criminal aliens in the U.S. today then just a few years ago, there are hundreds of thousands of known criminal aliens in the U.S."

"New crimes are committed every day by criminal aliens, so while we’re not seeing a decrease in crimes committed across this country, we are seeing a decrease in the removals of criminal aliens," Sessions said.

This cannot be blamed on a lack of financial resources, Sessions said, as Congress has increased funding. Still, deportations have plummeted and the administration is "doing substantially less with substantially more."

"Our goal should be to keep 100 percent of all criminal aliens out of the United States," Sessions said. "There’s nothing wrong or controversial about such a policy."

Saldana confirmed that "overall apprehensions on the border are declining" and the agency’s "removal numbers are lower than they have been in recent years."

However, she maintained that the administration is removing "at a greater proportion" dangerous criminals.

Of the 235,000 deportations in 2015, 59 percent of them were convicted criminals, according to Saldana, who said she is "very proud" of these statistics.

Yet, she said, "there are also times when despite our best efforts" criminal illegal immigrants "get released from our custody."

"ICE doesn’t willy nilly release people," she said. "We have to have a final order of removal from the immigration courts and proper travel docs to the country of origin for that particular national."

Update 10:00 P.M.: Jessica Vaughan, director of policy studies at the Center for Immigration Studies, told lawmakers that ICE is deporting just a small fraction of the criminal illegals currently residing in the United States.

"Last year ICE managed to deport just over 63,000 criminal aliens from the interior out of an estimated criminal alien population of over 2 million," Vaughan said.