WASHINGTON — The State Department improperly seized the passports of at least 31 American citizens trying to obtain vital records and other paperwork from the United States Embassy in Yemen, according to an inspector general’s report released on Friday.

The passports were taken between December 2012 and June 2013, just as Yemen’s fragile political system began descending into chaos. Consular officials claimed they confiscated the passports of citizens after finding that their printed names were false or fraudulent.

In many cases, the citizens had gone to the embassy to obtain American passports or birth records for children born in Yemen. Many had been living in the United States but, after their passports were seized, were stuck indefinitely in Yemen amid a widening civil war.

Yemen is now in the midst of the world’s worst humanitarian disaster, with millions on the brink of starvation.