The United States government has decided to bar Americans from visiting North Korea, the first time in years that the State Department has moved to block travel to another country.

The restriction comes amid rising tensions between the United States and North Korea, which has been testing intercontinental ballistic missiles and threatened to attack the United States with nuclear weapons. The ban also follows the death in June of Otto F. Warmbier, the University of Virginia student who was convicted of trying to steal a political propaganda poster from his hotel in Pyongyang. This is the first time in more than a decade that the State Department has taken such strong measures. It was in the early 1990s during Saddam Hussein’s regime that travel to Iraq was restricted.

“Due to mounting concerns over the serious risk of arrest and long-term detention, the department will soon impose a travel restriction on all U.S. nationals’ use of a passport to travel in, through or to North Korea,” Susan A. Thornton, the acting assistant secretary of the Bureau of East Asian and Pacific Affairs, said in a statement on July 25.

United States passports will be invalid for travel to North Korea beginning Sept. 1.

“We seek to prevent the future detentions of U.S. citizens by the North Korean regime to avoid another tragedy like that which Otto Warmbier and his family endured.”