The United States is ready to engage in talks "on the basis of mutual respect" with Iran as long as Tehran is willing to demonstrate that its program is for civilian purposes

The United States is ready to engage in talks "on the basis of mutual respect" with Iran as long as Tehran is willing to demonstrate that its program is for civilian purposes, the White House said on Friday.

"We have had a number of engagements with the Iranians and we'll continue to have conversations on the basis of mutual respect," Josh Earnest, the deputy White House spokesman, told reporters aboard Air Force One during President Barack Obama's flight earlier in the day to Missouri.

"And over the course of those conversations there will be an opportunity for the Iranians to demonstrate through actions the seriousness with which they are pursuing this endeavor," Earnest said.

The White House has said that an encounter between the two leaders is possible.

Earnest said there was no meeting scheduled between Obama and Rouhani, but his comments were the latest signal from the White House that it views Rouhani potentially as someone with whom it can do business, according to Reuters.

A senior Zionist minister said on Friday that Iran is on course to develop a nuclear bomb within six months and time has run out for further negotiations.

But in a call with reporters to preview Obama's U.N. speech, deputy national security adviser Ben Rhodes said Washington believed there was time to pursue diplomacy with Iran.

"We've always made clear that there's not an open-ended window for diplomacy, that we need to be moving forward with a sense of urgency," Rhodes said. "We do believe ... that Iran has not taken steps, for instance, to break out and weaponize its nuclear program. So even as we move with a sense of urgency here, we do believe that there's time and space to pursue diplomacy."