Washington  - US president-elect Barack Obama indicated his administration would move "swiftly" with new tactics in its approach to Iran to head off the impending nuclear crisis and block Tehran's support of terrorism.

Speaking Sunday in an interview with ABC news, Obama said he expected Iran to be "one of our biggest challenges" when he takes office January 20.

"We have a situation in which not only is Iran exporting terrorism through Hamas, through Hezbollah, but they are pursuing a nuclear weapon that could potentially trigger a nuclear arms race in the Middle East," Obama said.

Obama has previously indicated his willingness to conduct more direct diplomacy with Iran, a change from the Bush administration's refusal to negotiate directly until Iran stops enriching uranium, a process that produces weapons-grade bomb fuel.

But Obama has also said that he would not rule out the threat of military action.

"We are going to have to take a new approach," Obama said. "The international community is going to be taking cues from us in how we want to approach Iran."

Obama said he intended to send a signal that "we respect the aspirations of the Iranian people, but that we also have certain expectations in terms of how an international actor behaves." (dpa)