"The people who are raising the questions are people who have not seen the information," Powell told journalists accompanying him on a trip to Israel and the Palestinian territories.

Powell said Wednesday that Washington had information suggesting that Iran was "actively working" to adapt its missiles to carry nuclear warheads.

However, US paper the Washington Post then reported that Powell's information had been based on what one senior official called an "unvetted, single source".

Arriving in Israel, Powell said he stuck by his information.

The fact that Iran, which already has advanced missile technology and is accused by Washington of seeking to develop a nuclear bomb, wants to put the two together is "not surprising", Powell said.

Tehran has denied the accusations.

Powell suggested that informal contact could be had with Iranian officials at a conference on Iraq's future in the Egyptian resort of Sharm el-Sheikh on Monday and Tuesday.

"There may be meals where we are meeting together in a social setting," he said.

However, Iran earlier ruled out the prospect of any meeting with Powell on the sidelines of the conference, saying direct talks would be pointless as he is about to step down from his post.

"Powell had four years to change the attitude of the United States towards Iran but he didn't. Now he is not in charge anymore, and it would not be very useful to meet him," foreign ministry spokesman Hamid Reza Asefi told reporters.

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