Abolhassan Bani-Sadr, Iran's president until his 1981 ouster, said the talks have taken place in Germany through 'mediators who want a relationship between Iran and the U.S.A.'
Bani-Sadr told journalists his sources are informants in the Iranian government.
Bani-Sadr was a star witness at a Berlin trial that ended last week with the court ruling that Iranian leaders ordered the 1992 assassination of Iranian Kurds in the German capital.
Iranian exiles accuse the Iranian leadership of involvement in other killings of Iranian dissidents in Western Europe.
Bani-Sadr said like European countries, the U.S. has been conducting talks with Iran - but secretly and using mediators.
The reason for the talks, he said, is to examine the possibility of normalizing U.S.-Iranian relations.
He said Washington has set two main conditions for that to happen: that Iran swear off terrorism and any desires to obtain a nuclear arsenal.
Discussions on those issues and others have taken place in the German cities of Hamburg and Frankfurt, Bani-Sadr said. He did not say when the last supposed discussion occurred.
He demanded that all Western countries with secret contacts with Iran terminate them.
Bani-Sadr also alleged that the German government has known about 'and tolerated' past weapons deals conducted by Iranian intelligence agents on German soil.
Bani-Sadr, who lives in France, traveled to Bonn to try to persuade German politicians of the necessity of permanently ending the European Union's 'critical dialogue,' a two-track policy of doing business with Tehran while discussing issues of terrorism and human rights.