The Justice Ministry has indefinitely banned three U.S. citizens with confirmed criminal records of sex offense from entering South Korea.

The ministry said it recently denied visas to the three Americans, all of whom had either sexually abused minors or made obscene phone calls while working as counselors in the U.S.

All three were planning to teach English in Korea.

In February, the government placed a permanent visa ban on those with a history of sex offense in South Korea, the applicant’s country or a third country.

A total of 12 foreigners have been prohibited from entering the nation for having a record of sexual offenses.