The US Secret Service says another person not on the guest list was allowed into a White House state dinner for Prime Minister Manmohan Singh in November.

Officials have been reviewing White House security procedures after it was discovered that an attention-seeking couple - Tareq and Michaele Salahi - made their way into the party without an invitation and shook hands with the president.

Monday's acknowledgment brings the tally to three people who made it through Secret Service security at the White House without being on a guest list.

The Secret Service says someone travelling with the Indian delegation was allowed in. The service says this person was screened at the hotel with the rest of the Indian delegation who attended the state dinner.