Multilateral talks in Turkey over Iran's nuclear ambitions were said to be productive. Another round of negotiations was scheduled for May 23 in Baghdad.
Ramin Mehmanparast, a spokesman for the Iranian Foreign Ministry, said Tehran had a clear indication of which countries were genuinely interested in reaching a conclusion on the nuclear issue.
"It is also clear (which) countries make efforts to establish security in the region and which countries have a role in making regional countries insecure," he was quoted by the semiofficial Mehr News Agency as saying.
Mehmanparast offered few specifics.
Talks between Iran and U.N. Security Council permanent members -- the United States, Britain, France, Russia and China -- along with Germany in Istanbul were said to be amicable. Tehran before the summit had expressed frustration with Ankara's foreign policy decisions, however.
Iran, meanwhile, had said the presence of foreign military forces in the Persian Gulf was a source of contention.
The International Atomic Energy Agency had said there may be some military aspects to certain parts of Iran's nuclear program, though Tehran maintains its intentions are peaceful.