Alcan, the big Canadian aluminum maker, said Friday that a $28.6-billion hostile takeover offer from Alcoa remains inadequate, and that it is pursuing alternatives such as talks with other groups.

Alcan spokeswoman Anik Michaud declined to comment on reports that Rio Tinto , the world's second-largest miner, has asked investment banks to advise it on options, including a possible counterbid for Alcan.