On the same day that the anti-poverty group ACORN announced the launch of an "internal review" after four undercover videos exposed its workers offering advice on how to skirt federal laws, a fifth video surfaced that purports to show a worker offering to help bring underage girls into the U.S. for the purposes of prostitution.

The latest video was filmed in San Diego by conservative activist James O'Keefe, 25, and partner Hannah Giles, 20, who posed as a pimp and prostitute as they did in their previous undercover stings.

In the latest video, O'Keefe asked the man if Tijuana is the best place to bring the girls to cross over into the U.S.

• ACORN: A Brief History

The man replied "yes," because he has a lot of contacts there who can assist in bringing them across the border.

In another part of the video, the man asked O'Keefe how much he charges for Giles' services.

"Are you a potential client?" O'Keefe asked.

"No, no. I want to know," the man said. "How...what is it?"

The other videos released in recent days and posted on BigGovernment.com have prompted the firing of at least four ACORN employees in Baltimore and Washington and the launch of a criminal investigation by the Brooklyn District Attorney's Office.

Republicans, who have long criticized ACORN, which is under scrutiny for several voter-registration fraud cases, are urging the Justice Department to investigate ACORN. The Senate voted Monday to block the Housing and Urban Development Department from giving grants to ACORN, and the Census Bureau last week severed its ties with the group for the 2010 national head-count.

Earlier Wednesday, ACORN announced it is ordering an independent investigation. ACORN will work with its advisory council, which includes prominent supporters of President Obama, such as John Podesta, president of the nonprofit Center for American Progress, and Andrew Stern, president of the Service Employees International Union, to name an indepedent auditor and investigator, ACORN chief executive Bertha Lewis said in a written statement.

The investigation will examine all the systems and processess called into question by the video, Lewis said.

In addition, ACORN won't accept new admissions into its community service programs, effective immediately, and within the next few days will conduct staff training, she said.

Lewis said the steps were being taken in response to "the indefensible action of a handful of our employees."

"We have all been deeply disturbed by what we've seen in some of these videos," Lewis said, adding that the group "will go to whatever lengths necessary to re-establish the public trust."

Asked Wednesday about the controversy, White House press secretary Robert Gibbs said that "obviously the conduct that you see on those tapes is completely unacceptable."

"I think everyone would agree with that. The administration takes accountability extremely seriously," Gibbs said. "I think the Census Bureau evaluated and determined that this group could not meet the bureau's goal of achieving a fair and accurate count in 2010."

Rep. Gus Bilirakis, R-Fla., said he's asked the Federal Emergency Management Agency to repeal a nearly $1 million grant it awarded to ACORN earlier this month.

FEMA awarded $997,402 to ACORN in New Orleans on Sept. 4 as part of its Fire Prevention and Safety Grants program. The group plans to use the money to assess fire safety in the homes of low and moderate-income families and hand out smoke and carbon monoxide detectors and other fire prevention gear, ACORN's Brennan Griffin said.

FEMA had no immediate comment on Bilirakis' request.

Gibbs said he assumed that federal agencies "constantly evaluate to ensure that any grantee is living up to what has to happen in order to fulfill that grant application."