WASHINGTON (REUTERS) - The White House warned on Tuesday against expecting quick results from international talks in Geneva on Iran's nuclear program, saying the discussions are complex and technical and that economic pressures against Teheran would remain in place.

"We certainly want to make clear that no one, despite the positive signs that we've seen, no one should expect a breakthrough overnight," White House spokesman Jay Carney said at a briefing.

"Although we appreciate the recent change in tone from the Iranian government on this issue, we will be looking for specific steps that address core issues," he added.