NEW YORK - Simon Property Group Inc said it could not agree to conditions General Growth Properties Inc wanted to impose before talks about Simon's $10 billion bid for the No. 2 U.S. mall owner.

General Growth's terms for a nondisclosure agreement were not constructive and make clear your apparent interest in precluding our offer from moving forward or being considered by your stakeholders, Simon said in a letter its smaller rival.

In light of the lack of interest General Growth has shown to date in engaging with us, SPG clearly cannot, and we will not, accede to terms that do not guarantee us fair treatment in your process, Simon wrote in the letter.

It added the terms seem to be intended specifically to sideline us, while you pursue discussions with other parties -- as you have previously threatened to do -- without engaging with us.

General Growth was not immediately available for comment.

Simon stock closed up 0.7 percent at $77.72, while General Growth closed up 0.4 percent at $12.74 on Friday. (Reporting by Paritosh Bansal and Ilaina Jonas)