Rice warns Iran it could face new sanctions

"They are already paying consequences and, of course, there are other possible courses available to us," she said.

She added that the United States was looking at new steps to cut off more Iranian banks from the international financial system and could do so at any time over the nuclear issue as well as alleged terrorism financing.

"We will continue to designate entities as we find them trying to use the international financial system for ill-gotten gains," Rice said. "We're going to continue to do it and we are going to continue to do it aggressively because Iran should not be in a position of using the banking system to pass profits made from terrorism or proliferation."

The comments came during on two-day trip to California's Silicon Valley, where Rice is showing Miliband high-tech firms and meeting with venture capitalists who are funding research into clean, sustainable energy projects.