The U.S. Secret Service is investigating how an uninvited couple was admitted to a White House state dinner for visiting Indian Prime Minister Manmohan Singh.

The Washington Post says the couple from the northern part of the U.S. state of Virginia slipped through several layers of White House security despite not being on the guest list for Tuesday's dinner.

Michaele and Tareq Salahi later boasted about their feat on a Facebook Web page, posting photos of themselves posing with U.S. Vice President Joe Biden, White House Chief of Staff Rahm Emanuel and other guests.

Secret Service spokesman Ed Donovan says the party crashers went through the same security screening for weapons as other dinner guests and did not pose a danger to the event.

He says an initial finding indicates that a White House checkpoint did not follow proper procedures to ensure that the couple was not on the guest list.

The spokesman also says secret service agents were protecting top dignitaries at the dinner at all times.

The Washington Post describes the Salahis as aspiring reality television stars and polo-playing socialites.

Some information for this report provided by AFP, AP and Reuters.