A Brazilian newspaper has reported that Xstrata and Glencore want Vale to increase its bid to $US95 billion ($A106 billion), a price more than what the Brazilian mining company is willing to pay.
Both companies are remaining tight lipped on the deal.
Earlier this week it was reported that Xstrata had rejected an informal offer of just under £40 per share, valuing the bid at around £38.9 billion or $A84 billion.