Otto Frederick Warmbier (C), a University of Virginia student who was detained in North Korea since early January, is taken to North Korea's top court in Pyongyang, North Korea, in this photo released by Kyodo March 16, 2016. Mandatory credit REUTERS/Kyodo

WASHINGTON (Reuters) - Americans who travel to North Korea despite ongoing warnings risk “unduly harsh sentences” for actions that would not be considered a crime in the United States, the U.S. State Department said in its latest travel warning on Monday.

The department, in a detailed warning against such travel, cautioned that at least 14 U.S. citizens have been detained in North Korea in the past 10 years and that American travelers should be aware that possessing any media criticizing the country could considered a crime.

Its strong advice came after two Americans were sentenced in recent weeks in North Korea and when international tensions are increasingly high with the reclusive country over its nuclear weapons program.

Last month, North Korea’s Supreme Court sentenced Korean-American Kim Dong Chul, 62, to 10 years hard labor after he admitted to committing “unpardonable espionage” including stealing military secrets, according to North Korean media.

American student Otto Warmbier was sentenced to 15 years of hard labor in March for trying to steal an item with a propaganda slogan, North Korean media reported.

Washington has condemned the punishments, saying North Korea is using U.S. citizens to push its own political agenda. In the past, North Korea has used detained Americans to push for high-profile visits from the United States, with which it has no formal diplomatic relations.

U.S. officials have long warned Americans against traveling to North Korea, and on Monday it outlined a dozen specific actions that “whether done knowingly or unknowingly - ‘have been treated as crimes” in an attempt to further caution travelers.

Showing disrespect toward North Korean leader Kim Jong Un or former leaders, criticizing the government, having an unauthorized interaction with residents, taking unapproved photographs and shopping at certain stores have all been considered crimes, the department said.

Americans traveling there should not expect protection from tour groups or guides or have expectation of privacy, it added.