NEW YORK (Reuters) -- 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 to its smaller rival.
The letter is the latest salvo in a battle that has rapidly escalated after the No. 1 U.S. mall owner went public with its offer for General Growth on Tuesday, following months of behind-the-scenes maneuvering.
General Growth, which became the biggest real estate failure in U.S. history when it filed for bankruptcy in April, has said it is pursuing an exit plan, which includes emerging from bankruptcy as a stand-alone entity as well as potential deals.