The U.S. State Department has issued a travel warning for North Korea.

The department on Thursday said on its Web site that the U.S. and North Korea do not have diplomatic relations, and that as the case of Aijalon Gomes illustrates, travel to North Korea is not routine or risk-free.

In a separate travel warning, the department warned U.S. citizens against entering the North without first having received explicit official permission and an entry visa from the North Korean government. The department said that Pyongyang will prosecute and sentence those who enter the North without proper documentation.

It is the first time for Washington to issue such a warning for the North.