North Korea may have a miniature nuclear weapon, believe some intelligence officers in the United States. The claim comes after Congress recently heard about the possibility.

Adm. William Gortney, head of US Northern Command, earlier told Congress that it would be “prudent” to believe that North Korea was in possession of a miniaturized nuclear weapon. Now a number of US officials echo the same belief.

One of the officials believes that North Korean Supreme Leader Kim Jong Un was determined to prove his doubters wrong. Washington is yet to be convinced about the North’s capability to have such a nuclear power.

Pentagon Press Secretary Peter Cook appreciated the commanders who would like to be “prudent” by assuming that Pyongyang might have a miniaturized warhead. However, the assumption “does not mean that they have that capability,” CNN quoted him as saying. “They’ve not demonstrated that.”

Recent photos showed Kim standing beside a device. According to North Korea, the one in the picture is a miniaturized nuclear device. However, US analysts are still scrutinizing its authenticity.

The North earlier tested a solid-fuel rocket engine. According to a US expert, the Asian country is still far away from developing long-range missiles. Michael Elleman referred to claims that the rocket motor had burned for 57 seconds and said it was too long.

“The long burning time as indicated by the control room panel and the low-pressure burn would suggest that this might be designed for the upper stage of a multi-stage rocket system,” Korea Times quoted the missile engineer as saying.

The US officials, who believe Pyongyang may have a miniaturized nuclear warhead, are not sure if the device will work, even though the North claims it will.

US authorities, however, acknowledge that the North has been making developing an advanced version of its KN-08 intercontinental ballistic missile.