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Responding to a rapidly evolving scandal, the Secret Service is looking into claims that its agents brought prostitutes back to their hotel rooms while in El Salvador ahead of President Obama's visit in March 2011.

The incident would have occurred more than a year before the alleged misconduct earlier this month in Colombia, which has brought international embarrassment to the agency and raised questions about how widespread the after-hours carousing is abroad.

Seattle channel KIRO-TV reported Thursday that, according to a government subcontractor who was there, agents and military personnel went to a San Salvador strip club where some of them paid for sexual favors in the VIP room. At least two agents, the source reportedly said, brought escorts back to their rooms.

Secret Service spokesman Edwin Donovan downplayed the latest allegations in a statement to Fox News.

"The recent investigation in Cartagena has generated several news stories that contain allegations by mostly unnamed sources," he said. "Any information brought to our attention that can be assessed as credible will be followed up on in an appropriate manner."

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    One agency official, though, told The Associated Press that the Service is investigating the latest reports in order to determine their credibility.

    Rep. Elijah Cummings says Secret Service Director Mark Sullivan told him and Rep. Darrel Issa "there is nothing credible that has come forth."

    He indicated that they had "about 50 people" they needed to interview and that the Secret Service had been in contact with the TV reporter who first reported the El Salvador allegations.

    Cummings, a Democrat, and Issa, a Republican, lead the House Committee on Oversight and Government Reform.

    Other lawmakers on Capitol Hill voiced concern at the latest developments in the scandal.

    "This latest allegation only reaffirms the need for independent investigations by the Inspector General," Sen. Charles Grassley, R-Iowa, said in a statement. "Regardless of whether the incidents were previously referred to internal investigators, they need to be examined. There are rumors flying about various incidents over several years about the conduct of Secret Service personnel, as well as other law enforcement and military personnel in locations around the world. The only way to put to rest the rumors of a much wider problem is for the allegations to receive transparent and independent reviews."

    The El Salvador report is indeed the latest blow to both the Secret Service and the military in the widening scandal.

    Defense Secretary Leon Panetta, on a trip to South America, acknowledged that three Marines and an embassy employee were disciplined after allegedly hurting a prostitute in Brazil.

    "They are no longer in this country, they were reduced in rank and they were severely punished for that behavior," he said.

    A senior U.S. official told Fox News the U.S. Embassy paid for the prostitute's medical bills, though she is now suing the embassy.

    The Washington Post also quoted several sources in an article earlier this week claiming that some of the agents implicated in the Colombia scandal are protesting their treatment by agency top brass -- because senior employees supposedly tolerated similar incidents in the past.

    "It has happened before," one agent told the Post. "This is not the first time."

    Though Donovan downplayed the anonymous sources in these articles, the KIRO-TV report on El Salvador claimed the owner of the strip club in the incident confirmed U.S. Secret Service agents visited his club -- allegedly for at least three consecutive nights.

    The owner said he doesn't allow prostitution inside, though he couldn't speak for what happens outside the club. The owner also reportedly said officials from the FBI, DEA and U.S. embassy routinely visit his club.

    The Drug Enforcement Administration issued the following statement Thursday afternoon: "We have seen news reports mentioning (DEA) agents in El Salvador. We are unaware of any allegations of misconduct. Any information that can be assessed as credible will be followed up in an appropriate manner and immediately."

    The Secret Service and the military have moved to investigate and discipline the two dozen individuals implicated in the Colombia scandal.

    Of the dozen agents on the Secret Service side, the agency has cleared three of serious misconduct. It has ousted eight agents and permanently revoked one agent's security clearance.