TEHRAN, Aug. 1 (Xinhua) -- The recent U.S. sanctions against the Iranian foreign minister is a "childish" act, Iranian President Hassan Rouhani said here on Thursday.

By sanctioning the Iranian foreign minister, "they (Americans) are resorting to childish behaviour," Rouhani said, reacting to the Wednesday's sanctioning of the Iranian Foreign Minister Mohammad Javad Zarif by Washington, amid high tension between the two sides.

"They (Americans) were claiming that they want to talk with no preconditions," Rouhani said, adding that however, they sanction the Iranian foreign minister.

"This means that they have lost the power of rational mind," he pointed out.

The U.S. Treasury Department on Wednesday sanctioned Zarif, alleging that he "acted or purported to act for or on behalf of, directly or indirectly, Iranian supreme leader," who was placed under U.S. sanctions in June.

Zarif quickly responded to the U.S. action on social media, quipping that he was grateful to be considered a "huge threat" to the U.S. hardliners.

"It has no effect on me or my family, as I have no property or interests outside of Iran," Zarif said. "Thank you for considering me such a huge threat to your agenda."