Potash Corp
said on Tuesday its suitor BHP Billiton has called many of its customers, a move that the fertilizer maker condemned as being inappropriate and highly unethical.

BHP, the Anglo-Australian mining giant, earlier this month, launched a $38.6 billion (25.0 billion pounds) hostile takeover bid for Potash Corp, the world's largest fertilizer company.

Potash Corp, in a letter to its customers, said it recently learned that Chris Ryder, the head of potash marketing for BHP Billiton, made calls to many of them.

Since the purpose of BHP Billiton's call clearly was not to solicit your potash order from BHP Billiton's Jansen project ... we consider this contact to be inappropriate, said Stephen Dowdle, Potash Corp's head of sales, in the letter dated August 30.

BHP's Jansen project, located in Canada's potash-rich province of Saskatchewan, is still years away from completion. It is expected to produce 8 million tonnes of potash annually when completed, but BHP's directors have yet to approve the start of development.

Potash Corp, which has rejected BHP's $130 a share offer as grossly inadequate, questioned the purpose behind BHP's calls to its customers.

We can only assume that BHP Billiton's purpose is to sow seeds of doubt and confusion about the future of Potash Corp by raising questions about our ability to do business across the nutrient spectrum as well as the future location and makeup of our sales organisation, said Dowdle, in the letter to customers.

Potash Corp, which included the letter in a regulatory filing, did not provide additional details about comments that BHP may have made to its customers.

BHP declined to comment on the matter.

The Saskatoon, Saskatchewan-based potash producer said it remained focussed on ensuring its customers receive products and services in a timely manner.