WASHINGTON — A congressional investigative panel is demanding documents and testimony from an embattled U.S. defense contractor accused of failing to promptly disclose human trafficking on a base in Iraq.

An investigation by The Associated Press this month found that Sallyport Global fired two of its investigators after they uncovered evidence of the trafficking as well as alcohol smuggling and major security violations at Balad Air Base.

In a letter to Sallyport’s Chief Executive Officer, Victor Esposito, the House Committee on Oversight and Government Reform ordered Sallyport to turn over an extensive list of documents and to make company representatives available to answer questions before June 9. The letter signed by the committee’s chairman, Jason Chaffetz, a Republican, and top Democrat, Elijah Cummings, cited the AP’s reporting.

“The allegations include prostitution, alcohol smuggling, timesheet fraud, concealment from Department of Defense auditors, and retaliation against employees whose duty it was to investigate these allegations,” the letter says.

Sallyport Global Holdings was paid nearly $700 million in federal contracts to secure Balad Air Base, home to a squadron of F-16 fighter jets as part of the U.S.-led coalition against the Islamic State group.

In a statement, Sallyport Chief Operating Officer Matt Stuckart said the company looked forward to speaking to the panel.

The allegations include prostitution, alcohol smuggling, timesheet fraud, concealment from Department of Defense auditors, and retaliation against employees whose duty it was to investigate these allegations.

“Sallyport takes any suggestion of wrongdoing at Balad Air Force Base in Iraq very seriously and strongly disputes the claims made by two former employees,” said Matt Stuckart, Chief Operating Officer. “Since taking over operations January 2014, Sallyport has helped turn Balad Air Base into an instrumental part of the fight against ISIS.”

In their letter, the lawmakers wrote, “Protecting American troops and facilities abroad is a solemn responsibility.” They then raised concerns about the fired investigators’ charge that the company shut down their investigations.

“Making matters worse, according to the report, Sallyport management short-circuited internal investigations and fired the employees responsible for them when they requested to interview Sallyport management suspected of wrongdoing,” they wrote.

After the AP’s report, the company denied the allegation that company managers had shut down an investigation into alcohol smuggling and human trafficking. They later acknowledged that after learning that the original probe had been stopped, lawyers had asked for a second investigation into new reports of prostitution on the base.

According to the investigators’ original report in February 2016, four Ethiopian women who were suspected of working at a hotel in Baghdad as prostitutes moved to the base after customers at the hotel complained about contracting sexually transmitted diseases. Those customers included Sallyport employees, the investigators said.

The House panel is also scrutinizing allegations raised in another AP investigation that contractors have reported fraudulent data in a key military program to counter IS propaganda online.

Based in Reston, Virginia, Sallyport was founded in 2003 to work in Iraq on reconstruction, and has since expanded its operations globally.