Facebook (Nasdaq: FB), the No. 1 social networking site, said it has started to offer UK users over 18 the chance to play online bingo and slots for cash. For now, the Menlo Park, Calif., company is barred from offering gambling in the U.S.

Facebook said it started Bingo and Slotz Friendzy apps in partnership with Gamesys, one of the UK's top online gambling operators. Julien Codorniou, Facebook's chief of gaming for Europe, Middle East and Africa said Facebook would seek other European partners.

"Gambling is very popular and well-regulated in the UK...for millions of bingo users it's already a social experience [so] it makes sense [for us] to offer that as well," Codorniou told the Financial Times.

Shares of Facebook rose 37 cents to $22.29 in early Tuesday trading.