The United States remains waiting Iran's official response to the International Atomic Energy Agency (IAEA)'s proposal to use Iran's own low-enriched uranium and send it out to be enriched to fuel their research reactor, State Department spokesman Ian Kelly said on Tuesday.

"We are going to wait to see what the official response is before we give any kind of possible reaction," Kelly told reporters.

"What we're waiting for is a response to the IAEA," Kelly said. "We understand it's supposed to come the middle of this week, and so I assume in the next couple of days we'll get a response."

Kelly made the remarks hours after Iranian official mass media said that Tehran will accept the framework of the IAEA drafted nuclear proposal but wants significant changes into it.

Iran reportedly will announce its decision within the next 48 hours on the United Nations-drafted deal for Tehran to send low- enriched uranium abroad for further processing.

The United States has voiced its support for the U.N.-drafted proposal that the enriched uranium with a higher purity needed for research reactor in Iran would be produced abroad.