Travelers wait in line at Los Angeles International Airport, the United States, June 30, 2017. [Photo/Xinhua]

WASHINGTON - The US State Department said on Friday that American citizens will soon be banned from travelling to the Democratic People's Republic of Korea (DPRK).

The ban on all US citizens' use of a passport to travel to, through or in the DPRK resulted from "mounting concerns over the serious risk of arrest and long-term detention" of Americans there, said State Department spokesman Heather Nauert in a statement to Xinhua.

According to Nauert, the ban was expected to be formally declared next week and would take effect 30 days after the formal declaration.

For Americans seeking to travel to the DPRK for "certain limited humanitarian or other purposes," they may apply to the State Department for a special validation passport, Nauert added.

Before the introduction of the travel ban, the State Department had for long strongly warned Americans against travelling to the DPRK.