Mannesmann, the German telecoms group fighting a £85bn bid from British rival Vodafone, is planning a new rights issue to fund further acquisitions if it remains independent, Klaus Esser, chief executive, said yesterday.

In a series of interviews with German newspapers Mr Esser went on the offensive against Vodafone's hostile bid before launching his company's de fence document within the next week.

He told Börsenzeitung, a Frankfurt stock exchange newspaper, that he explicitly sought a rights issue worth "substantial billions in euros" to underpin the company's strategy and rejected the argument of Chris Gent, Vodafone's chief executive, that Mannesmann's £20bn takeover of mobile phone operator Orange would limit its capacity to raise capital.

Mr Esser said that the planned float of the company's engineering and automotive business in July would raise euro 4bn (£2.5bn) - and these would be used not to fund the Orange purchase but "future transactions in the year 2000".

He told the Frankfurter Allgemeine Zeitung that Mannesmann planned to take on further majority stakes in European telecom companies after extending its holdings in Arcor, Infostrada and Omnitel - and taking over Orange - last year.

The Mannesmann defence strategy is focused on the group's integrated approach to mobile and fixed-line telephony and Mr Esser told the Frankfurter Allgemeine Zeitung that new integrated products offering access to both the internet and telecommerce would be available later this month.

Castigating Vodafone as "a loss-making concern", Mr Esser said that it would have to book an unprecedented €100bn or more in goodwill if it won Mannesmann - and compensate Mannesmann shareholders with up to euro 60bn in cash if it was forced to sell on Orange at an unfavourable price.

Shares in the Düsseldorf-based group lost euro 11.40, or 5%, to close the session at euro 217, while its British predator also lost nearly 5% of its value in a declining market for telecoms stocks.