The reason behind the tension is because of the fact that North Korea and South Korea are on the brink of a war. America was going to help and fight for South Korea but then the Afghan war started, so they have their hands full unfortunately. North Korea however have China on their side. Hopefully this answer helps you a little.
You have to state the event, for me to tell you, the reasons as to why Korea acted in the given way.
Reason for tensions were: Quartering, Impressment and the Stamp Act
North Korea attacked South Korea.
No, Americans are generally not allowed to enter North Korea due to travel restrictions and political tensions between the two countries.
russians
It increased tensions in the Cold War between communism (USSR) and capitalism (USA).
Pittsburgh is 13 hours behind Korea
the spread of Islam.
racial tensions
to reunify the country
No, it is not possible to fly directly from the United States to North Korea due to political tensions and travel restrictions between the two countries.
The Communist invasion of South Korea.North Korea's invasion of South Korea