Iran's official IRNA news agency says that Foreign Minister Javad Zarif has been summoned before parliament to explain his recent public stroll with U.S. Secretary of State John Kerry.

The IRNA report on Sunday says that 21 parliamentarians have demanded that Zarif explain his 15-minute walk through the streets of Geneva with Kerry on Jan. 14, on the sidelines of ongoing nuclear negotiations between Iran and "P5+1" global powers — the U.S., Britain, France, Germany, Russia and China. The parliament members called it a "diplomatic mistake."

Zarif and moderate President Hassan Rouhani have faced intense skepticism from Iranian hard-liners, who believe they are making too many concessions to the West in negotiations to limit the scope of Iran's nuclear program.

Tehran and Washington broke diplomatic ties after Iran's 1979 revolution.