Unconfirmed reports from defectors claim that people living near the Punggye-ri test site suffer from mysterious symptoms and that babies have been born deformed.
"I hope we can avoid war", says Boykin, "but diplomacy is not the answer". It's not clear how a nuclear payload would affect flight time but North Korea is said to be close to readying a warhead, at least a small one, for an ICBM, North Korea watchdog 38 North has reported.
"We thought we were dying because we were poor and we ate badly".
South Korea and the United States began five days of air combat drills on Monday, less than a week after Pyongyang tested an intercontinental ballistic missile it said put all of the U.S. mainland within its reach.
The US's F-22 is fully stealth and North Korea likely can't hope to down it.
But the report says worldwide pressure can be effective, pointing to Uganda's recent decision to expel North Korean officials after years of receiving police and military training from the country's army.
Canada scraps buying 18 Boeing fighter jets amid trade dispute
In August 2017, Canadian officials travelled to Australia to inspect the F/A-18 aircraft the country is planning to buy instead. At a conference in Boston in November, Bombardier CEO Alain Bellemare said: "Boeing is underestimating what they are tackling.
North Korea issued threats in advance of a planned aerial drill on December 4 involving US and South Korean forces in the region, but America and its ally have responded by going right on ahead with it.
Zhang Liangui, a professor of worldwide strategic research at ChinaÂ's Central Party School, said: "North Korea has fired a new missile that can reach the United States and the U.S. is conducting large scale navy drills with South Korea".
With the recent launch of an intercontinental ballistic missile known as the Hwasong-15, it has become apparent to many observers that Pyongyang is not being dissuaded from abandoning its nuclear weapons program.
"The two sides also exchanged views on relations between the two parties and the two countries, and on the Korean Peninsula issue and other issues of common concern", Xinhua said.
The supersonic bombers have previously flown over North Korea in pairs as a show of force after past missile launches by the isolated nation's military.
The drill is taking place as the UN's political chief Jeffrey Feltman visits Pyongyang for dialogue, in a rare visit by a senior United Nations official.