Yahoo! has started a beta trial of paid-for search results on its mobile internet service in the UK and US.

The launch, starting with a group of just under 100 advertisers, forms part of the portal’s plan to extend pay per click services to mobiles.

Both it and Google, which has not yet provided advertising on its mobile search service, are in a race to attract mobile users through partnerships with operators.

The group has already conducted tests of sponsored mobile search results in the UK and Japan, as well as targeted trials in the US.

Our test deployments have been very successful, with strong advertiser demand and consumer engagement, which makes us very excited to bring our sponsored search listings to an even wider audience,” said Steve Boom, senior vice president, mobile and broadband, Yahoo!

Yahoo! said it would expand the number of participating advertisers as the beta phase progresses.

The results of the trial will be worth watching, considering research still points to low uptake of mobile web services.