Asked at a conference in Amsterdam whether there was a timeframe for the talks, Michael Fries said: "No timeframe. I can't add anything else."

Vodafone, the world's second largest mobile company, said in June that it was in talks with Liberty Global, Europe's largest cable operator, over the possibility of swapping selected assets to enable them to better compete with rivals.

(Reporting By Yorul Bahceli, writing by Thomas Escritt, editing by William Hardy)