WASHINGTON (CNN) -- The acting inspector general of the Department of Homeland Security has announced he will launch a separate investigation into the Secret Service prostitution scandal.
The "field work is beginning immediately," acting Inspector General Charles Edwards said in a statement Monday.
"We have maintained close contact with the USSS (United States Secret Service), coordinating with them as their internal investigation continued. Last week, with the initial stages of the USSS internal investigation nearing completion, we notified the USSS of our intent to conduct a comprehensive review of this matter," his statement said. "As we notified the USSS last week, OIG's (Office of Inspector General) field work is beginning immediately."
The development comes as Secret Service Director Mark Sullivan faces a pair of deadlines Tuesday to answer dozens of questions relating to the scandal.
Homeland Security Chairman Peter King, R-New York, submitted 50 questions to Sullivan, while House Oversight Committee Chairman Darrell Issa and Rep. Elijah Cummings, the panel's ranking Democrat, have 10 questions they want answered, including a precise time line of exactly what went down in Cartagena.
"The incident in Cartagena is troubling because Secret Service agents and officers made a range of bad decisions," they said.
Issa and Cummings also sent a letter to Defense Secretary Leon Panetta requesting details of the military investigation by May 8.
The incident last month before President Barack Obama's trip to the Summit of the Americas in Colombia involved Secret Service and U.S. military members who allegedly consorted with prostitutes.
Twenty-four people have been linked to the scandal: 12 from the Secret Service and 12 from the military.
In their correspondence to Panetta, Issa and Cummings said security personnel showed an "alarming lack" of "character" and "judgment."
Nine of the Secret Service members have resigned or are being forced out, and three others were cleared of serious misconduct, while a separate military investigation has yet to announce any measures against the members allegedly involved.
The U.S. Southern Command expects to finish questioning the 12 military personnel early this week before forwarding its findings to military lawyers for review, and then to Gen. Douglas Fraser, commanding general of the U.S. Southern Command, a Defense Department official said Monday.
On Friday, the Secret Service distributed new rules for its agents on assignment intended to prevent a repeat of such alleged misconduct, according to two government sources familiar with the resulting investigation.
Called Enhanced Standards of Conduct, the new guidelines given to all Secret Service personnel make clear that standards of behavior required in the United States apply on missions abroad, the sources said.
Effective immediately, the new standards require detailed briefings before each trip that will include safety precautions and any necessary designations of establishments and areas that are "off limits" for Secret Service personnel, the sources said.
Also in the new standards, foreigners are banned from Secret Service hotel rooms at all times, except for hotel staff and host nation law enforcement and government officials on official business, according to the officials, and all Secret Service personnel are prohibited from going to a "non-reputable establishment."
The new standards specify that U.S. laws apply to Secret Service personnel when traveling, rendering invalid the excuse that specific activity is legal in the foreign country, the officials said.
In addition, the new guidelines allow moderate alcohol consumption when off duty, but prohibit alcohol consumption within 10 hours of reporting for duty or at any time when at the hotel where the protected official is staying, the officials explained.
An additional supervisor from the Office of Professional Responsibility will now accompany the "jump teams" that bring vehicles for motorcades and other transportation, the officials said. Agents involved in the Colombia incident were part of such a jump team.
Allegations of further transgressions by agents have emerged after the initial reports of heavy drinking and consorting with prostitutes last month before President Barack Obama arrived in Cartagena for the Summit of the Americas.
Recent claims include an account from El Salvador described by CNN affiliate Seattle TV station KIRO as very similar to the Colombia scandal, involving members of the Secret Service and other government agencies.
The KIRO report cited an unnamed U.S. government contractor who worked extensively with the Secret Service advance team in San Salvador before Obama's trip there in March 2011.
The source said he was with about a dozen Secret Service agents and a few U.S. military specialists at a strip club in the city a few days before Obama arrived. The men drank heavily at the club, and most of them paid extra for access to a VIP section where they were provided sexual favors in return for cash, the source told the station.
The station reported that the strip club's owner corroborated the allegations. The owner confirmed that a large number of agents, and some military escorts, "descended on his club" that week and were there at least three nights in a row, KIRO reported.
The owner said his club routinely takes care of high-ranking employees of the U.S. Embassy in San Salvador as well as visiting agents from the FBI and U.S. Drug Enforcement Administration, KIRO said.
The government contractor source said he told the agents it was a "really bad idea" to take the strippers back to their hotel rooms, but several agents bragged that they "did this all the time" and "not to worry about it," KIRO reported.
Defense Secretary Leon Panetta said Thursday that his department is not investigating any of its troops over the reported incident in El Salvador. But the State Department is questioning its embassy staff in El Salvador about the allegations, spokeswoman Victoria Nuland said Thursday.
The Drug Enforcement Administration also is prepared to look into, "in an appropriate manner and immediately," allegations that it deems "credible" regarding its agents in El Salvador, agency spokesman Rusty Payne said. But he added that, while the DEA has seen news reports, "we are unaware of any allegations of misconduct."