After North Korea's provocative activities recently, the United States announced they would put further sanctions on North Korea. Does this mean the U.S. still has any sort of economic or diplomatic ties with North Korea?
Seemingly, not many:
As North Korea and the United States have no formal diplomatic relations, Sweden acts as the protecting power of United States interests in North Korea for consular matters.
More about it can be read here.
From this page you can see that:
Most forms of U.S. economic assistance, other than purely humanitarian assistance, are prohibited. The United States has provided food and other emergency aid to North Korea during times of famine and natural disasters. The United States has also assisted U.S. NGOs in providing aid to fight the outbreak of infectious diseases and to improve farming practices and agricultural output in rural areas.
The United States imposed a near total economic embargo on North Korea in 1950 when North Korea attacked the South. Over the following years, some U.S. sanctions were eased, but others were imposed. In the wake of the DPRK’s cyber-attack targeting Sony Pictures Entertainment, Executive Order 13687 imposed new sanctions against the government of North Korea and the Korean Workers’ Party, effective January 2, 2015. U.S. economic interaction with North Korea remains minimal.
South Korea has factories in North Korea staffed by North Korean workers. South Korea pays the North Korean government for this labor, not the workers. The U.S. buys some of the products from these factories. It's called the Kaesong Industrial Complex. It may be closing down now, but the U.S. took advantage of the North Korean labor for a long time.
I don't think there is...
Here is the source from NPR..
Samantha Power says, from 4:20～"I mean, interestingly, they haven't been willing to rely...", so if you listen to the all the radio, well, you can see Kim Jung Un, or North Korea is going their way regardless of what the U.S does...haha. ( Sorry).