UPDATE 1-Facebook 4th-quarter revenue rises more than expected

(Adds after-hours stock rise, financial details)

SAN FRANCISCO, Jan 29 (Reuters) - Facebook Inc's fourth-quarter revenue jumped 63 percent, beating Wall Street targets, as the Internet company's mobile ad sales continued to accelerate.

Shares of Facebook were up 7 percent at $57.36 in after-hours trading on Wednesday.

The world's largest social networking company said that revenue from mobile ads represented 53 percent of its total advertising revenue in the last three months of the year, or $1.24 billion, versus the 49 percent proportion that mobile ads represented in the third quarter.

Facebook said it now has 1.23 billion monthly users, with 945 million accessing the service on a smartphone or tablet.

Overall revenue in the fourth quarter rose to $2.585 billion, compared with $1.585 billion in the year-ago period and above the $2.33 billion expected by analysts polled by Thomson Reuters I/B/E/S.

Facebook reported net income of $523 million, or 20 cents a share, versus $64 million or 3 cents a share in the year-ago period. Excluding certain items, Facebook said it earned 31 cents a share.

(Editing by Matthew Lewis)