US Defense Secretary Jim Mattis says analysis continues on North Korea’s most recent missile test, but he doesn’t believe its intercontinental ballistic missile (ICBM) poses an imminent threat to the United States.

“It has not yet shown to be a capable threat against us right now … we’re still doing the forensics analysis,” Mattis told reporters at the Pentagon.

Last month, North Korea said it had successfully tested a new type of ICBM that could reach all of the US mainland and South Korea and US-based experts said data from the Nov. 29 test appeared to support that.

Mattis did not elaborate on what was lacking in the test to show it was not a capable threat.

He said himself immediately after the test that the missile had gone higher than any previous North Korean launch and that it was part of a research and development effort “to continue building ballistic missiles that can threaten everywhere in the world, basically.”

US-based experts, some of whom have been sceptical about past North Korean claims, said last month that data and photos from the test appeared to confirm North Korea had a missile of sufficient power to deliver a nuclear warhead anywhere in America.

But experts and US officials have said questions remain about whether it has a re-entry vehicle capable of protecting a nuclear warhead as it speeds toward its target and about the accuracy of its guidance systems.

South Korea’s Defense Ministry said this latest test put Washington within range, but Pyongyang still needed to prove it had mastered re-entry, terminal stage guidance and warhead activation.

Some US based experts believe North Korea could be only two or three tests away from being able to declare the missile operational.