The foreign ministry will investigate whether South Korean workers detained in a U.S. immigration raid last week faced human rights violations and raise the issue with Washington if necessary.

A ministry official said Monday that the workers' employers would first gather their employees' accounts and that the government would follow up directly if needed.

He added that Seoul and Washington had agreed that the incident reflected “structural issues” and that South Korea would document the case for use in future discussions with the United States.

The official noted that earlier consular interviews in the U.S. had focused on urgent matters and did not capture detailed testimony regarding possible rights violations.

On reports that detainees had been told to sign documents presented by U.S. Immigration and Customs Enforcement, the official said detainees had not been forced to admit to violating their stay conditions.

He added that the workers’ B1 visas remain valid despite their detention and repatriation and that talks regarding visa rules are ongoing through a bilateral working group.