The worrying assessment once again calls into question America's anti-missile capabilities, and whether it and its allies can protect themselves from the threat of a nuclear-tipped ICBM.
- How high? -
Defense officials did not elaborate on Mattis's remark about the missile's elevation, but on July 4, in a test that Kim Jong-Un called a gift for the "American bastards," a North Korean rocket soared to an altitude of 2,802 kilometers (1,741 miles) and flew 933 kilometers.
According to David Wright, a co-director and senior scientist at the Union of Concerned Scientists, news reports the missile reached more than 4,500 kilometers in altitude would give it a massive range.
"If these numbers are correct, then if flown on a standard trajectory rather than this lofted trajectory, this missile would have a range of more than 13,000 kilometers (8,100 miles)," Wright wrote on his organization's blog.
"Such a missile would have more than enough range to reach Washington, DC, and in fact any part of the continental United States."
After the July 4 launch, experts had said Alaska was in range, so the latest test marks a dramatic and rapid increase in North Korea's potential reach.
- Missile defenses -
The United States has spent decades and billions of dollars developing technologies to stop an incoming ballistic missile, and the US military still has faith these systems can protect against a North Korean missile attack.
"The (South Korea)-US alliance remains confident that we can still defend against any North Korean threat," Pentagon spokesman Colonel Rob Manning said shortly after Tuesday's launch.
America and its allies have several technologies at their disposal, none of which is infallible.
To take out an ICBM, America has the Ground-based Midcourse Defense (GMD) system at its disposal.
Installed at Fort Greely, about 100 miles outside Fairbanks in Alaska, and California's Vandenberg Air Force Base, the GMD can hit an incoming missile in space.
The missile blasted outside Earth's atmosphere and smashed into a dummy ICBM target, destroying it in a direct collision.
But the GMD system has had a checkered record in previous tests -- failing in earlier launches against slower-moving targets -- and it could be overwhelmed by a barrage of incoming missiles.
- What other defenses? -
Aside from the GMD, the United States and its allies also have at their disposal what is known as the Aegis Ballistic Missile Defense System (AEGIS).
The ship-based system's highly sensitive radars and sensors feed ICBM-tracking data to the GMD facilities in California and Alaska, and AEGIS is itself capable of intercepting shorter-range missiles.
Some experts say the AEGIS system may also one day have a limited ability to intercept ICBMs.
In the meantime, the US military this year began deploying the Terminal High Altitude Area Defense (THAAD) system to South Korea, capable of destroying short, medium and intermediate-range missiles in their final phase of flight.
That move infuriated China, which has argued the deployment would further destabilize the situation on the Korean peninsula.
The US and its allies South Korea and Japan also have Patriot Advanced Capability-3 interceptor batteries.
But these are designed to protect against a regional threat and would have limited effect against an ICBM.
In Europe, nations have an array of missile defenses but these are primarily focused against shorter range missiles that could come from Russia or the Middle East.
(Except for the headline, this story has not been edited by NDTV staff and is published from a syndicated feed.)