Gen. David Petraeus has ordered an investigation into claims that a top Army official instructed a military team to manipulate visiting U.S. dignitaries using "psychological operations" so they would approve more resources for the Afghanistan war.

Rolling Stone reported that the command of Lt. Gen. William Caldwell, who is in charge of training Afghan troops, tried to tap members of the military's "information operations" unit to use their skills on visiting senators and congressmen, among others. The goal, according to the article, was to convince the officials to provide more troops and money.

A spokesman for Caldwell said the story was "absolutely false." Asked whether Caldwell or his staff used the psychological tactics against visiting senators, the spokesman said, "absolutely not."

Two senators also played down suggestions they were manipulated to support the war effort.

But Fox News spoke with the accuser, Lt. Col. Michael Holmes, who stood by his allegations. He said he was "badgered" for months to get information on senators and other visitors.

"It was, 'What are these people wanting from us? What is it that we can tell them that will get them to give us more resources, more people, more money ... make them vote our way in Congress' essentially?" Holmes told Fox News. He said he got a written "directive" from Caldwell's office to find out what dignitaries "did for us" and what "we need to do next time in order to make things better."

He told Fox News the military has since retaliated against him by putting out "spurious information," but stood by his claim that the military had asked his unit to do something that was "over the line." He added that the order did not come from Caldwell himself, but from his chief of staff.

Responding to accusations by military officials that he had an "ax to grind," Holmes said:

"Do I have an ax to grind? Yeah. But the ax is this. If they can do this to a lieutenant colonel, what are they doing to the sergeants out there? I have a lot of education and training. ... I knew where to go and what the rules were and weren't."

Petraeus' office issued a brief statement Thursday morning saying the Afghanistan commander has ordered an investigation "to determine the facts and circumstances surrounding the issue."

Pentagon spokesman Col. Dave Lapan said Thursday that the investigation will seek to determine whether the actions taken were inappropriate or illegal.

Lapan, while not offering any denial of the claims made in the article, said it's not unusual for "psy-ops" personnel to be asked to do things outside their normal duties. For instance, it would not be inappropriate for Caldwell to ask one of the officers in the unit to get data on visiting congressional delegations. The critical question concerns what information was being gathered and how it was intended to be used.

Speaking to the general's character, current and former U.S. military officers who worked with Caldwell said he is an example of a modern Army officer who was trying to bring the Army's "strategic communications" into the 21st century, encouraging the units he commanded at Ft. Leavenworth, the Army's premier training facility, to use social media, blogging and Wikipedia as part of their efforts to shape their message. Defense Secretary Robert Gates praised Caldwell just last week for his efforts training Afghan forces.

"If you had to line up the smartest guys in the Army, he'd be at the top of the list. He gets 'communications'," said an Army public affairs officer familiar with Caldwell.

The Rolling Stone article centered on allegations by Holmes, a leader of the "information operations" unit. He said Caldwell was looking for more than typical background information about visiting senators. Holmes told the magazine the office wanted a "deeper analysis of pressure points we could use to leverage the delegation for more funds."

A senior U.S. military official whose unit deals with "psy-ops" told Fox News Holmes was not officially trained by the Army in this kind of warfare.

Holmes, in the interview with Fox News, acknowledged "psychological operations" was not his specialty -- but he said it's part of what his team works with.

Holmes, a member of the Texas National Guard, has a strategic communications firm in Dallas, Texas named SyzygyLogos LLC, which he runs with his business partner Laural Levine, who served with him as an Army major in Afghanistan and is mentioned in the Rolling Stone article.

According to the magazine article, when Holmes' unit first arrived in November 2009, the team believed their mission was to evaluate the effects of U.S. propaganda on the Taliban and local population.

Holmes claimed he resisted the order to gather information on Americans and told the magazine his unit was retaliated against.

According to the article, Holmes later became the subject of an investigation, which cited him for, among other things, going off base in civilian clothes and drinking alcohol. A timeline of events provided to Fox News by a senior U.S. military official showed that in March 2010, a lawyer looking into the legality of the directive to Holmes found information suggesting Holmes may have been engaged in an inappropriate relationship with another officer, identified in the article as Levine. Holmes denied the charge. The lawyer also noted the two went off post in civilian clothes to consume alcohol.

Those reportedly singled out in the "information operations" campaign included Sens. John McCain, R-Ariz.; Joe Lieberman, I-Conn.; Jack Reed, D-R.I.; Al Franken, D-Minn.; and Carl Levin, D-Mich. Other diplomats and think-tank analysts were also targeted, according to the article.

The Smith-Mundt Act of 1948 was passed by Congress to prevent the State Department from using propaganda techniques against U.S. citizens.

Levin, in a statement Thursday, said he has long supported a troop buildup among Afghan forces.

"For years, I have strongly and repeatedly advocated for building up Afghan military capability because I believe only the Afghans can truly secure their nation's future," Levin said in a statement. "I have never needed any convincing on this point. Quite the opposite, my efforts have been aimed at convincing others of the need for larger, more capable Afghan security forces, and that we and NATO should send more trainers to Afghanistan, rather than more combat troops."

Franken, who traveled to Kabul with Levin in January 2010, stressed his objectivity in assessing the briefings he received.

"While the briefings provided me with a helpful update on what was happening on the ground, I knew that I would have to crosscheck their assessment by talking to other military officials, diplomatic officials, outside experts and troops in the field, and I always raise skeptical questions when discussing this topic," Franken said in a written statement.

Fox News' Jennifer Griffin and Justin Fishel contributed to this report.