"From what we know of North Korean missiles, the propulsion technology in particular is fairly primitive with no digital or electronics to be hacked", said Schilling said.
In a sign of Beijing's hardening attitude, the Global Times, a state-run tabloid, said in an editorial on Monday that China could enforce "stricter measures" against North Korea, including a ban on oil exports, or join a USA -led effort to block the North's access to worldwide financial markets.
North Korea's deputy United Nations ambassador, Kim In Ryong, accused the USA of creating "a risky situation" for a nuclear war and said that the North is ready to react if the US "dares opt for a military action". "We'll be conducting more missile tests on a weekly, monthly and yearly basis", he told the BBC.
For decades, USA officials have made clear to their Chinese counterparts that the United States won't barter economic or other foreign policy issues in exchange for support on the North Korean issue - sending the signal that the U.S. position on the issue was in the interests of global stability.
President Donald Trump, eager to stop rapid advances in North Korea's nuclear and ballistic missile programs, is signaling a break with decades of United States policy as he looks to coax China into ramping up the pressure on North Korea.
Kim stressed that US-South Korean military exercises being staged now are the largest-ever "aggressive war drill" aimed at his country, formally the Democratic People's Republic of Korea.
"The prevailing grave situation proves once again that the DPRK was entirely just when it increased in every way its military capabilities for self-defence and pre-emptive attack with a nuclear force as a pivot", he said. Foreign Ministry spokesman Lu Kang said tensions need to be eased on the Korean Peninsula to bring the escalating dispute there to a peaceful resolution. In one symbolic demonstration of the Trump administration's tough new approach, Pence chose to go outside his security arrangements to personally review the line between North and South Korea at the DMZ.
While the North regularly threatens America and its partners in Asia, the US and its allies in the region are by no means unprepared for a North Korean nuclear attack.
The Trump administration has said military action remains an option for dealing with North Korea. And he warned that any use of nuclear weapons by Pyongyang would be met with "an overwhelming and effective response".
Across the border South Korea's recently impeached president Park Geun Hye, herself the daughter of former dictator Park Chung Hee, was yesterday indicted by prosecutors on corruption charges.
"We believe Kim Jong Un has a clear ambition to develop an intercontinental ballistic missile capable of carrying a nuclear payload as far as the United States", Bishop said. As the vice president stood and looked on, North Korean soldiers quickly came out on their side of MDL and began taking pictures of Pence.
He said rolling back the hostile US policy toward the DPRK "is the precondition to solving all the problems in the Korean Peninsula".
It was therefore "entirely just" for North Korea to have access to nuclear weapons for self-defense, since it is directly exposed to the USA nuclear threat.
Instead he reiterated two Chinese proposals that the USA rejected.
U.S. Vice President Mike Pence arrived in Japan for talks Tuesday expected to focus largely on trade with America's anchor ally in the region.