Iran usually sends an observer to the Shanghai Cooperation Organization, a regional grouping set up in 1996 as an alternative to NATO that would allow Russia and China to counter US influence in Asia.
"Deputy Assistant Secretary for South and Central Asian Affairs Patrick Moon is planning to attend this Shanghai Cooperation Organization conference in Moscow on the 27th of March," State Department spokesman Robert Wood said.
"It's a conference about Afghanistan and its neighbors," the spokesman told the daily news media briefing in Washington.
The meeting comes days before the Dutch government hosts a similar United Nations-sponsored meeting in The Hague on March 31 that US Secretary of State Hillary Clinton plans to attend.
Clinton said Afghan and Pakistani officials would be invited, with NATO allies, donors, international organizations and "key regional and strategic" nations like Iran.
The administration of President Barack Obama has offered to engage longstanding US foes like Iran.
Wood said it was important for Moon to attend the conference in Moscow because "it's about Afghanistan and how… the international community can try to … better the situation on the ground.
"Even though we're not a member (of the Shanghai group), we're not an observer, we think it's important. We're glad we were invited, and we look forward to attending," he said.
"And hopefully we can get something constructive out of this conference," said Wood.
Asked if Moon would meet his Iranian counterparts at the meeting, Wood replied: "There are no plans for any substantive meetings with Iran."
But he added: "It's not unusual for US and Iranian officials to… cross paths during a multilateral meeting. So I'm not going to rule anything in or rule anything out.
"It is a conference about Afghanistan and its neighbors. Iran is certainly a neighbor of Afghanistan's. And so … we'll see," he said.
