U.N. Secretary-General Ban Ki-moon on Wednesday, following weeks of speculation and calls by Western governments, including the United States, that he not accept the Iranian government's invitation -- lest the visit be exploited by the regime for propaganda purposes -- announced through his spokesman that he will participate in the summit in Tehran.

The controversy could easily become a presidential campaign issue, as it could be viewed as a snub of U.S. foreign policy: The U.S., which pays about a quarter of the U.N.'s budget, couldn't convince Ban not to go, and there was no obligation for him to accept the Iranian invitation to the 16th Summit of the Non-Aligned Movement.

"The Secretary-General looks forward to the summit as an opportunity to work with the participating heads of state and government, including the host country, towards solutions on issues that are central to the global agenda, including follow-up to the Rio+20 Conference on sustainable development, disarmament, conflict prevention and support for countries in transition," U.N. spokesman Martin Nesirky said.

"The secretary-general also takes seriously his responsibility and that of the United Nations to pursue diplomatic engagement with all of its member states in the interest of peacefully addressing vital matters of peace and security," Nesirky said. "With respect to the Islamic Republic of Iran, the secretary-general will use the opportunity to convey the clear concerns and expectations of the international community on the issues for which cooperation and progress are urgent for both regional stability and the welfare of the Iranian people. These include Iran's nuclear program, terrorism, human rights and the crisis in Syria."

Nesirky said Ban can "speak on behalf of the entire international community, to make clear directly to the Iranian leadership what the world expects from Tehran and to encourage positive and constructive responses. Not to do so would be a missed opportunity."

Asked if Ban's visit would not dilute his critical messages of recent days, Nesirky said that the visit makes the extent of international concern all that much clearer.

Fox News' Jonathan Wachtel contributed to this report.