Americans traveled to North Korea for the last time, just a few days before the travel ban takes effect on September 1. These travelers have rushed their vacations to make use of the remaining days of flying to the hermit kingdom freely, CNN said.

Starting next month, U.S. passports will be marked invalid when traveling to the East Asian destination. Tour operators estimated that there are a few hundred Americans who head over to North Korea for travel or vacation purposes, the report added.

“U.S. passports will not be valid for travel to North Korea and tourists will be required to a specially validated passport in order to fly to or within North Korea,” State Department spokeswoman Heather Nauert told CNN.

Travel ban

The United States Department of State Bureau of Consular Affairs has issued a travel advisory, warning citizens not to travel to the Asian nation. The official statement said that this is due to the serious and escalating risks of arrests and detention of Americans in the region

The Secretary of State has restricted Americans to use their passports to travel either to or within North Korea unless they obtain a passport that has been scrutinized by the bureau. The U.S. and North Korea are currently in unpredictable relations, after recent events surrounding missile tests.

“Since the United States are not maintaining diplomatic relations with the hermit kingdom, the federal government has no means to provide the usual consular services the American citizens in North Korea,” the Bureau of Consular Affairs statement continued.

Tourists arrested

The statement also reported that at least 16 U.S. citizens have already been arrested in the East Asian nation during the past decade alone. Authorities in the region have detained people who traveled alone or have not been part of any tour group. However, the state department noted that even travelers with a tour guide could be vulnerable to these kinds of arrests.

North Korea has been imposing strict regulations to foreigners visiting their land. Showing disrespect to the leader Kim Jong Un, and exchanging currencies with unauthorized sellers are considered as crimes in the Asian nation.

CNN reported that the travel ban was issued around a month after the mysterious passing away of 22-year-old Otto Warmbier, a college student from Ohio. He was imprisoned in North Korea for almost one year and a half and was eventually returned to his parents in comatose. He never woke up since then.