North Korea detained another American tourist last month which now makes a total of three Americans detained in the communist regime.

The U.S. State Department has repeated its warning against travel in North Korea for U.S. citizens after it confirmed the North has another American citizen in custody.

The warning comes after the North’s Korean Central News Agency reported it had arrested American tourist Jeffrey Edward Fowle, who is believed to have entered North Korea on April 29 and detained in mid-May just before his departure.

The agency said the man was undergoing an investigation after having violated North Korean laws and visa regulations.

Citing a diplomatic source, Japan's Kyodo News said the man was detained after he was accused of having left behind a Bible in his hotel room.

Pyongyang is also holding Korean-American Kenneth Bae and another American tourist, Matthew Todd Miller. Bae was arrested in late 2012 and sentenced to 15 years hard labor on charges of trying to overthrow the regime through religious activity. Miller was detained this April and reasons for his detainment are not as clear.

The U.S. government is seeking consular access to the detainees through the Swedish Embassy which represents U.S. interests in North Korea.

It's very unusual for three U.S. citizens to be detained in the North at the same time.

This comes at a time when the North is working hard to attract foreign tourists.

Pyongyang has often used detainees as a bargaining chip to pressure Washington into dialogue. In past incidents, the North induced visits by former U.S. presidents and other influential figures. The North would then release the detainees through the envoys and use the case to jumpstart talks with the U.S.

Currently, the U.S. and North Korea are at odds over the North’s nuclear program and human rights conditions.

But U.S. President Barack Obama refuses to stray from his principles.

Some observers speculate this may be why the North urgently needed some kind of leverage to pressure the U.S. government.