Annan's spokesman, Stephane Dujarric, told RFE/RL that Annan had planned to discuss with Iranian officials cooperation on stabilization efforts in Iraq and Afghanistan, as well as UN reform.
But those talks were compromised by Iranian President Mahmud Ahmadinejad's threat last month to "wipe Israel off the map."
Annan condemned the remarks. Dujarric says Annan's decision to cancel the visit followed talks with representatives of the Iranian mission to the UN in New York.
"The secretary-general and the Iranian government have mutually agreed that this is not an appropriate time for him to travel to Iran. In light of the ongoing controversy, it would have been difficult to advance the agenda that he had wanted to discuss with the Iranian leadership," Dujarric said.
Annan plans to follow through with the rest of his upcoming trip to the Mideast. He will depart this weekend for Egypt, Saudi Arabia, Tunisia, and Pakistan. He is expected to address a major conference on Pakistan’s needs for post-earthquake rehabilitation.
Meanwhile, a senior British general said today that new bomb-making techniques and more sophisticated parts were entering Iraq from Iran.
Speaking from Al-Basrah in a teleconference with reporters, Royal Marines General James Dutton said more advanced technology for making improvised explosive devices (IED) seemed to be coming from Iran.
Dutton declined to say whether he thought the Iranian government was involved or if the technology was being brought into Iraq by individuals from Iran without the Iranian government's knowledge.
IEDs are the leading cause of death among coalition troops serving in Iraq.
The Pentagon announced yesterday it has allocated extra funds to finds ways of defending against IEDs.
THE COMPLETE PICTURE: RFE/RL's complete coverage of controversy surrounding Iran's nuclear program.
An annotated timeline
of Iran's nuclear program.