The United States will call for "even stricter sanctions on Iran to try to change the behavior of the regime," US Secretary of State Hillary Clinton said in a TV interview broadcast late Tuesday.

US Secretary of State Hillary Rodham Clinton.
Photo: AP

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Washington remained concerned about what Clinton called Iran's "pursuit of nuclear weapons," which could "be very destabilizing in the Middle East and beyond," Clinton told the private Venezuelan television network Globovision.

Earlier Tuesday, Chairman of the Joint Chiefs of Staff Adm. Mike Mullen said Iran was "very focused on developing [nuclear weapons] capability, and I think when they get it, or should they get it, it will be very destabilizing."

Mullen was speaking at the Center for Strategic and International Studies, in an address on military challenges in the Middle East, sponsored in connection with the embassy of the United Arab Emirates.

However, Mullen was similarly grim on the prospects that Iran's nuclear weapons program might be attacked preemptively, saying such an attack on Iran would be similarly destabilizing, as in both cases, "there are unintended consequences that are very difficult to predict in a very volatile, highly volatile part of the world."

Earlier on Tuesday, US President Barack Obama told CNN that the US has "absolutely not" given Israel a green light for a possible attack on Iran's nuclear facilities, saying diplomacy is his preferred course of action.

Obama was qualifying comments Vice President Joe Biden had made Sunday that left the impression the US would not stand in the way of an Israeli action. "We have said directly to the Israelis that it is important to try and resolve this in an international setting in a way that does not create major conflict in the Middle East," said Obama.

Video: Obama says absolutely no green light for Israel to attack Iran