President Barack Obama says published reports that the United States and Iran are planning to meet one-on-one after the election are "not true."

Obama made his denial during a presidential debate with Republican rival Mitt Romney.

Obama says the United States will keep Iran from getting a nuclear weapon, but he will not engage in negotiations that go nowhere. Obama adds that "the clock is ticking."

On Saturday, the White House said it is prepared to talk one-on-one with Iran to find a diplomatic settlement to the impasse over Tehran's reported pursuit of nuclear weapons, but there's no agreement now to meet.

The New York Times reported that the U.S. and Iran have agreed in principle to negotiations. The White House denied that any such agreement had been reached.