The market for mobile device advertising doubled in 2013 to $17.9 billion and is on pace for strong gains this year, led by Facebook and Google, a market tracker said Wednesday.

The research firm eMarketer said mobile ad spending increased 105 percent last year and is expected to jump another 75 percent in 2014 to more than $31.45 billion.

Facebook and Google grabbed the lion's share of the increase in 2013.

Google remained far ahead of its rivals, but saw its market share dip to 49.3 percent in 2013 from 52.6 percent in 2012, eMarketer said.

The biggest gains came from Facebook, whose market share jumped to 17.5 percent from 5.4 percent a year earlier.

Twitter also saw strong gains but its share was a modest 2.4 percent from 1.5 percent in 2012.

For 2014, eMarketer sees Google at 46.8 percent, Facebook at 21.7 percent and Twitter at 2.6 percent.

The huge growth in mobile ads show why these companies are concentrating on their mobile platforms.

According to eMarketer, just 11 percent of Facebook ad revenues worldwide came from mobile in 2012, but last year, that figure jumped to 45 percent and the figure will be around 63 percent this year.

Google is expected to get a third of its ad revenue from mobile this year, up from 23 percent in 2013, the report said.