The White House said on Thursday that the Obama administration was still reviewing Iran's recent response on the nuclear talks with world powers, reiterating that a diplomatic solution was possible on the Iranian nuclear standoff.

"We're reviewing the letter...I don't have a review to give to you," White House spokesman Jay Carney told reporters during a press gaggle aboard Air Force One.

Carney was referring to the response from Saeed Jalili, Iran's chief nuclear negotiator, to the letter that EU foreign policy chief Catherine Ashton sent in October last year, a move the West had been demanding as a precondition for the resumption of talks between Iran and the G5+1 over its controversial nuclear program.

The G5+1 comprises permanent UN Security Council members Britain, China, France, Russia and the United States, plus non- permanent member Germany.

"We've noted in the past that the Iranians needed to respond to that letter. So they have," he said. "But I don't want to make any qualitative judgments to their response."

Carney reiterated the stance of the Obama administration that there was "time and space" to a diplomatic solution to Iranian nuclear impasse if the Islamic republic chose to engage in " constructive behavior."

The West suspects that Iran is developing nuclear bombs under the cover of its nuclear program, while the Islamic republic insists the program is only for power generation and medical purpose.