U.N. human rights experts are calling on Iran to stop arresting and prosecuting journalists, saying a new crackdown on freedom of expression appears to be under way in the Islamic republic.

Special rapporteur on Iran Ahmed Shaheed says "increasing intimidation of journalists" has impeded their ability to do their jobs ahead of parliamentary elections in February.

A U.N statement cited the Nov. 2 arrest by intelligence operatives of five journalists allegedly accused of seeking to undermine Iran's government. The statement pointed to similar tactics before elections in 2013.

The experts called on Iran to release all journalists, including Washington Post reporter Jason Rezaian. He was detained in July 2014 and convicted on charges including espionage. The newspaper calls the verdict an injustice, and press freedom groups have criticized his detention.