The White House says it will continue to rely on international diplomatic pressure to deal with Iran's nuclear intentions.
White House National Security Advisor Condoleezza Rice says diplomacy is still the first choice.
"The United States has been very actively and aggressively involved in a diplomatic strategy to try and deal with threats of nuclear weapons development in Iran and North Korea," she said.
She says the international community is beginning to respond to American concerns about Iran's nuclear ambitions, noting the U.N.'s International Atomic Energy Agency is involved. On North Korea, she points to the creation of six-party talks with strong participation from China.
"These are tough problems. These are problems that developed in the 1990's. These are problems that we have been working on," said Ms. Rice. "And we will use many means to try and disrupt these programs."
During an appearance on the NBC television program, Meet the Press, Ms. Rice was asked about the possibility of covert action to disrupt Iran's nuclear program.
The question stemmed from a front page story in Sunday's New York Times, which quotes unnamed administration and intelligence officials as saying the diplomatic approach has had little impact. The Times says these officials believe the time is right to intensify covert efforts in Iran.
Condoleezza Rice did not specifically address the possible use of covert activity. She did, however, stress both the administration's reliance on diplomacy, and its willingness to look at other options if necessary.
"Obviously, the president will look at all the tools that are available to him," she said.
Ms. Rice emphasized that the international community will not accept a nuclear-armed Iran, and she vowed America will not sit idly by.
"I think you cannot allow the Iranians to develop a nuclear weapon," said Condoleezza Rice. "The international community has to find a way to come together and make certain that does not happen."
Iran says its nuclear program is for civilian use only. The United States has been skeptical from the start, saying a nation with vast oil reserves does not need to develop a nuclear power technology that could conceivably be diverted to military use.