By Veronica Ek and Adam Cox

STOCKHOLM (Reuters) - Mobile phone maker Sony Ericsson warned on Friday it would make no profit in the second quarter due to weaker demand for its more expensive phones, sending shares in co-parent Ericsson down more than 11 percent.

Only last week, Sony Ericsson's global marketing head James Marshall told Reuters the projections for the second quarter looked strong.

Sony Ericsson, which is owned by Ericsson (ERICb.ST: Quote, Profile, Research) and Sony Corp (6758.T: Quote, Profile, Research), said in a statement profits had been affected by moderating demand for mid- to high-end phones and product delays. It said the market was "challenging".

The news drove shares in co-parent Ericsson down 7.8 percent to 60.70 crowns by 1301 GMT, having sunk as low as 58.50 crowns.

"Sony Ericsson is feeling the effects of a dependence on mature markets which are being impacted by the global economic downturn," said Geoff Blaber, analyst at CCS Insight.

Analysts were braced for weaker market conditions after a dismal first quarter for the firm and continued signs that consumers are being hit by an international credit crisis, high oil prices and general economic anxiety.

But Friday's news suggested conditions were worse than thought, although they said the weakness appeared to have more to do with Sony Ericsson specifically than all handset makers.

"The problems seem not to be related to the whole market, not to the sector as such," said Evli analyst Mikko Ervasti.