The warning from the State Department specifically mentions potential threats faced by U.S.-Iranian dual nationals.
It notes that since 2009, Iranian authorities have prevented the departure from Iran of a number of Iranian-American citizens, in some cases for several months.
It also says a number of Iranian-Americans have been detained in the Islamic Republic on charges including espionage and posing a threat to Iranian national security.
"U.S. citizens who travel to Iran should exercise caution" in light of the tense political climate in the country, which has included outbreaks of violence since last June's disputed Iranian presidential elections, the advisory says.
The United States and Iran have no formal diplomatic ties, and tensions have persisted largely due to the lingering international dispute over Iran's nuclear program and Tehran's crackdown on pro-democracy protesters and the media.
Iranian Supreme Leader recently scolded Washington for "claim[ing] interest in just and fair relations" but acting in "opposite" fashion.
compiled from agency reports
