UPDATED 2:20 p.m. ET
(CBS News) WASHINGTON - The Secret Service sex scandal is getting wider.
The dispute over payment to a prostitute in Cartagena, Colombia, by a Secret Service agent has triggered new charges of hard partying and impropriety by agents around the globe.
Two weeks after the incident in Cartagena, the Secret Service is working to quickly wrap up that portion of the scandal, but there are reports of unprofessional behavior and rule-breaking by agents in four countries, going back 12 years.
On Capitol Hill, there are growing demands for an outside agency to take over the probe.
Seattle CBS affiliate KIRO-TV reported Thursday that Secret Service agents visited a strip club in El Salvador -- by the vanload -- in advance of President Obama's trip there in March 2011.
The Secret Service is looking into that report. The Washington Post and the Wall Street Journal have reported that Secret Service personnel traveling in 2009 with former President Clinton partied at strip clubs on a visit to Buenos Aires, Argentina, and that agents and White House staffers went to a Moscow night club known for its sexually charged atmosphere prior to Mr. Clinton's trip to Russia in 2000.
A Secret Service spokesman called those accusations just "rumors."
The new allegations come soon after a hearing Wednesday in which senators were assured that the Colombia scandal was an isolated incident.
"That's why we need thorough investigation not just by the White House, not just by DHS (Department of Homeland Security), but by Congress; that's part of our oversight responsibilities," said Sen. John Cornyn, R-Texas. "It's an obligation we owe the American people.
Secret Service spokesman Edwin Donovan said the agency was taking a preliminary look into the new reports. "Any information brought to our attention that can be assessed as credible will be followed up on in an appropriate manner," he said in a statement.
White House Press Secretary Jay Carney said the president won't pass judgment on whether there's a pattern of misbehavior at the Secret Service until all investigations have been completed.
"When we travel abroad on official trips," Carney said, "we are representing the people of this country, and we should do so by conducting ourselves in an appropriate manner."
The continued attention to what happened in Cartagena has upset the Colombians. Colombia's ambassador to the U.S. calls the media coverage "superficial, sensationalist and unfair," and is asking the White House for a new apology. The State Department says the president and Secretary of State Hillary Clinton did both apologize when they were in Colombia.