Speaking in an interview with CNN television, Khatami said "We are definitely worried and hopeful that such a thing will not take place, such attack will not take place."

"I think, in all honesty, the probability of something like that taking place are very low. And I believe the only power that can undertake -- can take such steps is the United States, and, quite frankly, I think the United States has caused itself enough problems in Iraq."

Khatami called for a diplomatic solution to resolve the nuclear standoff, saying "Through communication and negotiation, the needed guarantees can be given to give assurances that we're not pursuing the atomic weapon."

Iran has never sought to secure nuclear weapons, he noted. "It has never been the policy nor the mindset of any branch of the Iranian government to pursue atomic weapons, which can be the source of vast, numerous deaths in the world."

Iran rejected an Aug. 31 deadline to halt enrichment activities while the United States is urging the UN Security Council to impose sanctions against the Islamic republic.

Khatami, who served as Iranian president from 1997 to 2005, was described as a reformer in Iran's political arena. He is scheduled to attend a UN conference on the dialogue of civilizations speak in New York and address at the Washington National Cathedral on Sept. 7.

Khatami's schedule may also include speeches at the University of Virginia and to the Islamic group in Chicago. He may pay a private visit to Thomas Jefferson's home at Monticello, according to sources familiar with his trip.

"Mr. Khatami is free to meet with who he chooses and is able to speak freely in the United States," a White House official said on the condition of anonymity.

Khatami's visit comes amid high tensions between Washington and Tehran over Iran's suspected program to develop nuclear weapons and its alleged support for Hezbollah guerrillas whose attack on Israel last month led to the ongoing crisis in Lebanon.