Iranian President Hassan Rouhani said Thursday that Tehran is not afraid of negotiations with Washington, but the United States must first return to the 2015 Iranian nuclear deal, Tasnim news agency reported.

The U.S. officials have, so far, made several appeals for negotiations with Iran, Rouhani said in the northern city of Rasht.

"Americans have even asked five leaders of other countries in the past year to work as mediators to convince Iran to enter talks with Washington," he said, adding that however, the conditions and time are not ripe for such talks and meetings.

The United States must first return to the Joint Comprehensive Plan of Action (JCPOA), international term for the nuclear deal, and make up for its withdrawal from the nuclear agreement before any plan for talks with Iran, Rouhani stressed.

Rouhani on Wednesday said that, the United States is seeking to overthrow the Islamic establishment by exerting pressures on Iran.

The U.S. has reimposed sanctions on Iran, including its oil exports and banking sectors, following its exit from the landmark Iranian nuclear deal last May.