Pyongyang conducts fourth test in 12 days in protest against South Korea-US joint military exercises.
The US allows citizens of 38 countries – including South Korea, Japan and France – to enter for up to 90 days without a visa under a waiver programme.
But visitors who have travelled to eight countries, including North Korea, since March 1, 2011, are “no longer eligible”, as details posted on the US Customs and Border Protection website showed on Monday.
They will have to apply for tourist or business visas.
The other seven countries – that include Libya, Somalia and Syria – were already on the exclusion list.
The change will affect tens of thousands of people from visa waiver countries who have gone to North Korea as tourists or for other purposes in recent years.
It will also put a damper on South Korean President Moon Jae-in‘s hopes of promoting cross-border tourism projects for his citizens to visit their nuclear-armed neighbour.
South Korean media put the spotlight on top business leaders, including Samsung Electronics Vice Chairman Lee Jae-yong, who were part of Moon’s delegation to Pyongyang for a summit with North Korean leader Kim Jong Un in September.
A Samsung spokesperson declined to comment.
US citizens have been banned from visiting North Korea since 2017, a measure introduced after an American student detained in Pyongyang was released in a coma and died a few days later.