US officials have issued unusually stark warnings to its citizens to stay out of North Korea. The warning lists all the ways it is possible to get into trouble in the Hermit Kingdom, including "showing disrespect" to the country's current or former leaders, taking unauthorized photographs and shopping at stores not designated for foreigners.

If Americans do enter the country against the US State Department's advice, they should "have no expectation of privacy," officials warn.

All electronic and multimedia devices, including USB drives, CDs, DVDs, phones and tablets are subject to search, the department warned. If North Korea authorities allow travellers to keep their mobile phone while in the country, it will simply enable officials "to monitor your calls," the State Department said.

"It was a little bit more specific and a little bit more blunt in some ways," State Department spokesman, John Kirby, told CNN about the latest warning. "I think that's reflective of the increased tensions that we're seeing there on the peninsula and certainly the way, the manner in which the regime has acted out against foreigners on travel to North Korea."

The agency usually issues travel warnings every six months on a variety of countries, but recent legislation now requires it to issue travel warnings about North Korea every 90 days. At least 14 US citizens have been detained in North Korea in the last decade, including people travelling on their own and visitors in the country as part of a group tour.

Early this year, Otto Warmbier - a 21-year-old student from the University of Virginia - became the most recent US citizen taken into custody when he was busted during a backpacking trip for allegedly stealing a propaganda sign. He has been sentenced to 15 years of hard labour.

Because the US does not have formal diplomatic relations with North Korea, the State Department has no way of providing consular help to American travellers in distress and thus works through the Swedish Embassy.