Hundreds of American citizens have departed Iran using land routes over the past week since an aerial war between the Islamic Republic and Israel broke out, according to an internal State Department cable seen by Reuters.

While many left without problem, “numerous” citizens had faced “delays and harassment” while trying to exit, the cable said. It said, without giving further details, that one unidentified family had reported that two US citizens attempting to leave Iran had been detained.

The internal cable dated June 20 underscores the challenge Washington is facing in trying to protect and assist its citizens in a country with which it has no diplomatic relations and in a war in which the United States may soon get involved.

The State Department did not immediately respond to a request for comment. The cable was first reported by The Washington Post.