The door remains open for Iran to work with other countries on its nuclear program but the "picture is not a good one," US President Barack Obama's National Security Adviser James Jones said Sunday.
Speaking on CNN's State of the Union, Jones said the clock is ticking toward the end of the year.
That's when Obama has said it would be clear whether Teheran was ready to work with the United States, other UN Security Council members and Germany to assure the world it was not trying to build a nuclear weapon.
So far, the Islamic Republic has rejected calls to enter negotiations, and the US president is believed preparing to seek harsher international penalties against Iran.
Jones stressed that "the door remains open" for Iran to change course.
Jones also referred to al-Qaida leader Osama bin Laden, saying the terror group head spends time both in Afghanistan and in Pakistan.
Most recent US estimates have placed bin Laden inside Pakistan. But Jones, a retired general, said the al-Qaida leader is "sometimes on the Pakistani side of the border, sometimes on the Afghan side of the border."
The US military and its allies in Afghanistan are "going to have to get after that" to ensure bin Laden is "once again on the run or captured or killed," Jones said.
US Secretary of State Hillary Rodham Clinton also said it was important to capture or kill bin Laden and other leaders of al-Qaida.
Speaking Sunday on NBC's Meet the Press, Clinton said the fight against terrorists can make "enormous progress" even without his capture.
Earlier, US Defense Secretary Robert Gates said the US has not had any good intelligence for years on bin Laden's whereabouts.
Speaking on ABC's This Week, Gates said he could not confirm recent reports that bin Laden had been seen recently in Afghanistan.