Rio Tinto, the Anglo-Australian miner, has identified $15bn (€10bn) of asset divestments as it launched its defence against last month's $142bn takeover approach from rival BHP Billiton.

Guy Elliot, the company's finance director, said Rio Tinto has raised its asset divestment target from $10bn to $15bn following the completion of its strategic review, which he said had "highlighted approximately US$30 billion of potential divestments".