The gunman was subdued after shooting a security guard in the arm in the offices of the conservative lobbying group. NBC's Brian Williams reports.

Updated at 6:45 p.m. ET: A gunman who shot a security guard Wednesday at the Family Research Council office in Washington, D.C., was carrying a handgun and several additional rounds of ammunition, federal investigators told NBC News.

Washington, D.C., police say the man walked into the headquarters of the conservative Christian lobbying group around 10:45 a.m. When challenged by the security guard, the gunman shot the guard in the arm with a Sig Sauer 9 mm handgun he pulled from a backpack.

The wounded guard, identified as Leo Johnson, wrestled the gun away from the shooter and prevented him from hurting anyone else, police said.

The suspect was then detained by other guards, and both district police and the FBI responded. He was taken into custody by FBI agents. The FBI will have jurisdiction if the incident turns out to be a hate crime.

Kevin Lamarque / Reuters Members of the FBI enter the Family Research Council office after a shooting Wednesday in Washington, D.C.

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The suspect’s name has not been released, but two law enforcement officials told NBC News he is Floyd Corkins, 28, from nearby Herndon, Va.

Federal officials said the suspect the backpack also contained materials about Chick-fil-A restaurants.

Another official said the suspect bought the gun used in the shooting five days ago.

The FBI said the security guard is being treated in the hospital and "doing OK."

“The security officer here is a hero, as far as I’m concerned,” Metropolitan Police Department Chief Cathy Lanier told NBCWashington.com. “He did his job. The person never made it past farther than the front door.”

An armed man walked into the Washington headquarters of the Family Research Council and shot a security guard, according to authorities. NBCNews.com's Dara Brown reports.

Jacqueline Maguire, FBI Washington Field Office spokeswoman, also called the guard "a hero."

"And he did an excellent job of stopping the gunman from getting any further into the building and from anyone else getting injured or shot by him," she said.

One law enforcement official told NBC News it's fairly clear the Family Research Council was the man's target, though the FBI has yet to specify either a motive or the target of the attack.

The Associated Press reported that Corkins had been volunteering at a community center for gay, lesbian, bisexual and transgender people. Another official told the AP the shooter made a negative reference about the work of the Family Research Council before opening fire.

Tony Perkins of the Family Research Council sent an e-mail to members last month in support of comments by the restaurant chain's president, Dan Cathy, who criticized same-sex marriage.

The comments touched off a public clash. Supporters on "Chick-fil-A Appreciation Day" on Aug. 1 flooded the chain's franchises around the country and was countered with "kiss-ins" by same-sex couples at assorted locations Aug. 3.

On its website, the Family Research Council founded in 1983, says it advocates "faith, family and freedom in public policy and public opinion" and other issues. It lobbies against gay rights, abortion and embryonic stem cell research.

In a statement, Family Research Council President Tony Perkins said, "The police are investigating this incident. Our first concern is with our colleague who was shot today. Our concern is for him and his family."

Thirty-four gay rights groups issued a joint statement condemning the shooting:

"We were saddened to hear news of the shooting this morning at the offices of the Family Research Council. Our hearts go out to the shooting victim, his family, and his co-workers. The motivation and circumstances behind today's tragedy are still unknown, but regardless of what emerges as the reason for this shooting, we utterly reject and condemn such violence. We wish for a swift and complete recovery for the victim of this terrible incident."

White House spokesman Jay Carney said the president, who was traveling in Iowa Wednesday, was informed of the shooting shortly after 1 p.m.

"The president expressed his concern for the individual injured in the shooting and his strong belief that this type of violence has no place in our society," Carney said.

Republican presidential candidate Mitt Romney said in a statement that he was appalled. "There is no place for such violence in our society," he said. "My prayers go out to the wounded security guard and his family, as well as all the people at the Family Research Council whose sense of security has been shattered by today's horrific events."

This story includes reporting by NBC News' Andrew Mach and The Associated Press.

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