Zynga Inc slashed its 2012 earnings outlook after its quarterly results badly missed Wall Street's targets, sending its stock plunging more than 30 percent to a record low and dragging Facebook Inc shares down with it.

The largest provider of games on the world's No. 1 social network slashed its 2012 earnings outlook to 4 to 9 cents a share, sharply down from a previously projected 23 to 29 cents.

Zynga, which debuted just about half a year ago on public markets, has been struggling to sustain growth in the face of intense competition from rival casual games makers. It is trying to expand onto mobile devices.

The company founded by CEO Mark Pincus reported quarterly revenues of $332.4 million, below the average analyst estimate of $344.12 million, according to Thomson Reuters I/B/E/S.

Shares in Zynga, which began sliding before it released results, plummeted 35 percent to as low as $3.30 in after-hours trade, from a close of $5.078 on Nasdaq.

Facebook, which relies on the social gaming giant for some 15 percent of its revenue, slid almost 7 percent to $27.33, from a close on the Nasdaq of $29.34.