LONDON (Reuters) -European mobile group Vodafone ( VOD ) reported another deterioration in Germany, its biggest market, in its third quarter, a weak point amid otherwise stronger trading in Britain, Turkey and Africa.

Service revenue in Germany fell 6.4% in the quarter, worse than the 6.2% drop in the second quarter, which it said was mainly due to the impact of a change in pay-TV laws and to a lesser extent increased competition in mobile.

Chief Executive Margherita Della Valle said service revenue for the group accelerated to 5.2% in the three months to the end of December, driven by a step-up in the UK and strong performances in Turkey and Africa.

"We are continuing to invest in the turnaround of our German business and we are starting to see improving customer trends, although conditions have become more challenging in the mobile market," she said on Tuesday.

The company reiterated its guidance for the full year.