"The composition of the negotiating teams will include ambassadors of Iran and America in Baghdad, as head of the two teams, with observance of Iraqi officials," IRNA quoted Hasan Kazemi Qomi as saying Monday.
On Sunday, both Iraqi Foreign Minister Hoshyar Zebari and U.S. Embassy spokesman Philip Reeker confirmed Iran and the U.S. would hold talks Tuesday.
Kazemi Qomi said two officials from the Iranian Foreign Ministry and Supreme National Security Council, Hossein Ami Abdollahian and Reza Amiri, will accompany him to the meeting, according to IRNA.
Iraq's fragile government has been pressing for another meeting between the two nations with the greatest influence over its future, and Iran has repeatedly signaled its willingness to sit down.
But following the meeting in May, U.S. Secretary of State Condoleezza Rice and other U.S. officials said Iran had not scaled back what the United States alleges is a concerted effort to arm militants and harm U.S. troops.
Tensions also have risen over Tehran's detention of four Iranian-American scholars and activists charged with endangering national security. The U.S. has demanded their release, saying the charges against them are false.
At the same time, Iran has called for the release of five Iranians detained in Iraq, whom the United States has said are the operations chief and other members of Iran s elite Quds Force, which is accused of arming and training Iraqi militants. Iran says the five are diplomats in Iraq with permission of the government.
The United States broke off diplomatic ties with Iran following the 1979 storming of the U.S. Embassy in Tehran and the holding of American hostages for 444 days.