The White House says it is still waiting for a definitive response from Iran to a package of incentives designed to convince Tehran to suspend uranium enrichment. Officials say the latest comments from Iran's supreme leader, Ayatollah Ali Khamenei, are not the last word.

White House Spokesman Tony Snow says the Ayatollah's comments are ambiguous, and should not be seen as a formal reply from Iran.

He says there have been all sorts of statements coming from Tehran since the European Union's foreign policy chief, Javier Solana, delivered the incentive package to Iran's chief nuclear negotiator, Ali Lairjani.

"We have been pretty clear here," he said. "The original set of incentives was transmitted from Javier Solana to Ali Larijani. And we expect Ali Larijani to submit, transmit the response to Javier Solana."

During a session with reporters, Snow acknowledged that Khamenei holds considerable power in Iran. But he stressed that the United States is still waiting for a consistent, official response from Tehran.

"At this point the government of Iran has not spoken with one official voice and I daresay that various people speaking on behalf of the government of Iran have not spoken with a unified voice," he said.

The Ayatollah said Tuesday that Iran will not engage in negotiations on its right to use nuclear technology. However, he added if others acknowledge that right, Tehran is willing to negotiate controls, supervisions, and international guarantees.

Iran has said it will respond to the package put forward June 6 by the five permanent members of the U.N. Security Council and Germany by August 22. However, the Bush administration has made clear it wants an answer sooner, and that Iran should reply in a matter of weeks, not months.

Iran maintains its nuclear program is designed to meet energy needs. But the United States and its European allies say they are concerned Tehran's civilian program is really a cover for the development of nuclear arms.