EXCLUSIVE: A sudden influx of illegal immigrants from Mexico requesting asylum is overwhelming immigration agents in San Diego, forcing agencies to rent hotel rooms for some undocumented families and release others to cities around the U.S.

Documents obtained exclusively by Fox News show Immigration and Customs Enforcement has been paying for hotel rooms for dozens of recently arrived families to relieve overcrowding inside the San Ysidro and Otay Mesa, Calif., processing centers. Some ICE employees are working overtime and others have been asked to volunteer to work weekend shifts. “Duties include intake, placements, transports and release of family groups and unaccompanied minors,” according to a memo obtained by Fox News.

The surge has raised suspicions about what is driving the influx, amid claims that illegal immigrants have learned they can attempt to get asylum by using a few key words -- namely, by claiming they have a "credible fear" of drug cartels.

“This clearly has to have been orchestrated by somebody,” said former U.S. Attorney for Southern California Peter Nunez. “It's beyond belief that dozens or hundreds or thousands of people would simultaneously decide that they should go to the U.S. and make this claim.”

Sources say one day last week, 200 border-crossers came through the Otay Mesa Port of Entry claiming asylum while and as many as 550 overflowed inside the processing center there and in nearby San Ysidro.

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“People were sleeping on floors – they had nowhere to put them,” said one source, a long-time border agent and supervisor. “This shouldn’t be happening. Unless there is an immediate and well-publicized policy change, this situation will become another debacle.”

At a hotel near San Diego -- which Fox News agreed not to identify for security reasons -- ICE vans arrived several times over the weekend with immigrant families. They were escorted to the second floor by two armed, uniformed agents. Two border agents secured the entrance and side door.

Documents obtained by Fox News show that recently on a single day, dozens of illegal immigrants were being transferred to an area hotel where rooms cost $99 a night. Others were released to addresses in Texas, Florida and even Brooklyn, N.Y.

ICE sources say the addresses are almost always bogus. When they don’t show up for court, they are removed by an immigration judge in absentia.

Most of the immigrants came from Mexico, but others listed their native country as Haiti, Romania, Guatemala and Iraq. Some were over age 50, others were under a year old. Thirty were transported to a hotel. Seventy were released around the country.

Fox News spoke to four agencies responsible for the San Diego situation last week. All deferred to the Department of Homeland Security press office in Washington, D.C., which issued this statement:

“Credible fear determinations are dictated by long standing statute, not an issuance of discretion. The USCIS officer must find that a 'significant possibility’ exists that the individual may be found eligible for asylum or withholding or removal.

“If the credible fear threshold is met, the individual is placed into removal proceedings in Immigration Court. The final decision on asylum eligibility rests with an immigration judge.”

It is during this time – during removal proceedings – when illegal immigrants are released. Many don't show up, as 91 percent of asylum claims from Mexico are denied.

Asylum claims from Mexico are highly unusual and critics say this is an orchestrated sham – it's not about getting asylum, they say, but about overwhelming the system and getting a free pass into the U.S. and a court date for which no one will show up.

“Hundreds of thousands of people have never returned and the list of people for whom warrants are outstanding is phenomenal,” said Nunez. “We have a long history of people absconding from immigration hearings of one sort of another, they just blend back into the community.”

ICE sources say an estimated 600,000 to 800,000 illegal immigrants a year do not show up for their court date and disappear into the U.S.

The number of asylum claims is on the rise, almost tripling the last four years. Most come from Chinese, Egyptian and Ethiopian immigrants. Fewer than 200 a year come from Mexico, let alone 200 in a day. However, by claiming they have a “credible fear of persecution” if returned to Mexico, the immigrant is entitled to a series of interviews, hearings, proceedings and appeals that can drag on for years.

The initial evaluation usually is done in the border processing center by an asylum officer employed by USCIS.

Officials stress that meeting the "credible fear" standard is not a tentative asylum approval. It's simply a step in the process.

An immigration spokesman said last week: "The legal threshold for ‘credible fear’ is broad and low to ensure individuals who may face a 'significant possibility' of persecution ... have the opportunity to have their case heard before an immigration judge."

Last week, an asylum officer heard the claims of the "Dream 9," nine Mexican nationals brought to the U.S. as children. Even though seven of the nine lived, worked and went to school in Mexico without incident, they were granted asylum. Most thought they would be deported.

“The orders from Washington are to simply turn these people loose,” said Ira Mehlman, a spokesman for the Federation for American Immigration Reform. “All you have to say is you qualify for the Dream Act and/or you intend to apply, and they’re instructed by their higher-ups to simply turn these people loose, to set them free and let them pursue any path they want.”

There are 57 immigration courts and 231 immigration judges. Immigration courts handle 280,000 proceedings each year -- an average of 1,243 per year per judge, or four decisions per day.

Asylum can be granted if the applicant has suffered past persecution or has a "well-founded fear of persecution" on account of race, religion, nationality, membership in a social group, or political opinion in their native country.