North Korea says it will put two detained US men on trial, accusing them of "committing hostile acts".
Matthew Miller and Jeffrey Fowle had been investigated and would be brought before a court, the state news agency KCNA reported.
It said that suspicions about the two men had been confirmed by evidence and the pair's own statements, but gave no further details.
A US-Korean missionary, Kenneth Bae, is currently serving a 15-year sentence.
He was arrested in November 2012 and later convicted of trying to overthrow the North Korean government.
US attempts to secure his release have so far proved unsuccessful, despite fears over his health.
Both of the US nationals to be put on trial entered North Korea on tourist visas.
Jeffrey Fowle entered North Korea on 29 April and was detained in early June as he was leaving the country, according to North Korean reports.
Japanese agency Kyodo said Fowle was arrested because he left a Bible at a hotel.
Matthew Todd Miller was detained on 10 April, KCNA reported.
The agency said he had torn up his tourist visa, shouting that he had "come to the DPRK [Democratic People's Republic of Korea] after choosing it as a shelter".
North Korea has in the past been accused of using arrested Americans as diplomatic bargaining chips.
The US wants Pyongyang to abandon its nuclear ambitions in return for economic and diplomatic incentives, but talks on a deal agreed in 2007 have been stalled for several years.
Last year, North Korea carried out its third nuclear test and launched a three-stage rocket that Washington called a banned test of long-range missile technology.
The US has no formal diplomatic ties with North Korea. But in the past, senior US figures including former President Bill Clinton have travelled to the country to ensure the release of American detainees.
Religious activity is severely restricted in the North and missionaries have been arrested on many previous occasions.
Kenneth Bae, the highest-profile of the currently detained Americans, was sentenced to 15 years' hard labour in May 2013.
North Korea says he used his tourism business to form groups to overthrow the government.
The US has tried on at least two occasions to arrange a visit by a senior human rights envoy, Robert King, to discuss his case, but Pyongyang has cancelled both these visits.
Detainees from other nations can be treated differently - earlier this year, Pyongyang deported Australian missionary John Short, who was detained after apparently leaving Christian pamphlets at a tourist site.