By Patricia Zengerle

WASHINGTON - A couple who penetrated layers of security to enter a State Dinner at the White House this week without an invitation met US President Barack Obama in the receiving line, a White House official said on Friday.

The Washington Post first reported that a Virginia couple not on the official guest list, Tareq and Michaele Salahi, crashed the White House party but were never seated at a table in the South Lawn tent where the dinner was held.

The White House asked the U.S. Secret Service for a full review of what happened and the agency, charged with protecting the president and other high-level officials, is conducting a comprehensive review of the security breach at the dinner in honor of Indian Prime Minister Manmohan Singh.

"The Secret Service is deeply concerned and embarrassed by the circumstances surrounding the State Dinner on Tuesday, November 24," Secret Service director Mark Sullivan said in a statement.

He said preliminary findings of the investigation determined that established procedures were not followed at an initial checkpoint. The couple went through magnetometers and other screenings, but should not have been allowed to enter the event at all.

"That failing is ours," Sullivan said.

The Secret Service has said no one at the dinner was ever in danger. The White House could not say immediately whether the couple had also met Singh.

A dozen pictures posted on the Facebook website appeared to show the couple posing with dinner guests including Vice President Joe Biden, Washington Mayor Adrian Fenty, CBS News anchor Katie Couric and White House Chief of Staff Rahm Emanuel.

The Secret Service said it was continuing its review and measures had been taken to prevent any future such incident.

"The men and women of the Secret Service put their lives on the line every day to protect us. They are heroes and they have the full confidence of the President of United States," White House spokesman Nick Shapiro said.

"The White House asked the United States Secret Service to do a full review and they are doing that. The United States Secret Service said they made a mistake and they are taking action to identify exactly what happened and they will take the appropriate measures pending the results of their investigation," he said.

(Editing by Todd Eastham)