US mobile shoppers spent more than $10 billion in the first half of 2013, in a segment making strong inroads in retailing, a survey showed Tuesday.

US mobile shoppers spent more than $10 billion in the first half of 2013, in a segment making strong inroads in retailing, a survey showed Tuesday.

The comScore survey showed from consumers using smartphones or tablets in the first half rose more than 25 percent from the same period a year ago and now account for 9.5 percent of all digital ecommerce sales.

"While are already extremely influential in the overall buying process, they are also beginning to drive a meaningful percentage of digital commerce," said comScore chairman Gian Fulgoni.

"One out of every ten consumer e-commerce dollars is now spent using either a smartphone or a tablet, and growth in this segment of the market is outpacing that of traditional e-commerce by a factor of 2x, which itself is growing at rates in the mid-teens."

The report showed "m-commerce" revenues, which are highly seasonal, at $5.9 billion in the first quarter and $4.7 billion in the second quarter. With the largest spending likely in the , sales are on track to top last year's pace of $20 billion.

The report said smartphones accounted for some six percent of e-commerce sales in the first half of 2013 and tablets for 3.5 percent.

The biggest categories for m-commerce were apparel and accessories, computer hardware and event tickets. Video game, consoles and accessories showed the highest percentage of digital commerce spending via m-commerce at 23.7 percent, according to comScore.

More than half of US adults own a , and about one-third have a , according to recent surveys.