Tensions are high on the Korean Peninsula as the international community tries to assess the leadership style of North Korean leader Kim Jong Un. He took control over the country after leader Kim Jong Il, his father, died in December.
The State Department issued a travel advisory warning U.S. citizens of the risks, while not routine, of traveling to North Korea.
Four U.S. citizens were arrested for entering the country illegally in 2009 and a fifth was detained for unspecified reasons in 2010.
"The government of North Korea imposes heavy fines and long prison sentences with hard labor on persons who enter the country without a valid passport and a North Korean visa," the warning reads.
A 23-member delegation from the Pacific Council on International Policy, which has headquarters in California, toured North Korea in August at the invitation of Pyongyang.
The delegation visited Pyongyang, an industrial complex and the demilitarized zone separating North and South Korea.
A diplomatic official in Washington told the Yonhap News Agency the visit was "deemed meaningful."