UPDATE 5-Cliffs Natural says activist investor rejects offer to end proxy fight
* Says offered to let Casablanca appoint two independent directors
* Says a third director was to have been appointed by mutual agreement
* Says postponing record date for annual shareholder meeting
* Casablanca denies making a postponement request
March 7 (Reuters) - The war of words between Cliffs Natural Resources Inc and Casablanca Capital escalated on Friday, after the activist investor rejected an offer to end a proxy battle to win control of the iron ore miner's board.
Casablanca, Cliffs' fifth-largest shareholder with a 5.2 percent stake, wants Chief Executive Gary Halverson gone, and the company to spin off its "riskier" international operations from cash-generating U.S. assets.
The hedge fund, which started its campaign in January, nominated six directors for election to Cliffs' 11-member board on Thursday.
Cliffs had offered to let Casablanca appoint two independent directors and a third director was to have been appointed on mutual agreement, the company said in a statement issued early Friday morning.
Cliffs also said it acceded to Casablanca's request to postpone the May 13 record date - the date on which an investor must own shares to be entitled to vote - for its annual meeting. Continued...