Seoul, South Korea (CNN) -- North Korea says it plans to prosecute two American tourists that it detained earlier this year, accusing them of "perpetrating hostile acts." 

The North Korean government had previously said it was holding the two U.S. citizens, Jeffrey Fowle and Matthew Miller, but hadn't said what it planned to do with them. 

"According to the results of the investigation, suspicions about their hostile acts have been confirmed by evidence and their testimonies," the North's Korean Central News Agency (KCNA) reported Monday. 

"The relevant organ of the DPRK is carrying on the investigation into them and making preparations for bringing them before court on the basis of the already confirmed charges," the report said, using using an abbreviation of the country's official name, the Democratic People's Republic of Korea. 

The U.S. State Department called on North Korea to release the two men on humanitarian grounds. 

Asylum bid? 

North Korea said in late April that it had taken Miller into custody, claiming he had come to the country seeking asylum and had torn up his tourist visa. 

It announced the detention of Fowle in early June, saying he had violated the law by acting "contrary to the purpose of tourism." 

It didn't provide details at the time on what exactly he was accused of doing. But the Japanese news agency Kyodo cited unidentified diplomatic sources as saying that Fowle was part of a tour group and that he was detained in mid-May after allegedly leaving a Bible in a hotel where he had been staying. 
Were there visitors?
ourists 