North Korea Possibly Readying For Another Missile Test, Report Says

North Korea might be preparing to conduct another nuclear test after "brisk activity" was spotted at a nuclear research facilities base, South Korea’s spy agency said Thursday.

South Korea's Yonhap news reported the National Intelligence Service (NIS) also saw signs of the base getting ready for another missile launch. During a parliamentary audit, the NIS told lawmakers there was an "active movement" of vehicles around the nuclear facility in Punggye-ri, which seemed to indicate that the North Korean regime would resume its provocative testing. The latest test was in September and reportedly caused damage to the base.

In another incident at the site Tuesday, as many as 200 people were reported to have died when a North Korean tunnel under construction collapsed.

NIS also said Pyongyang would continuously push to develop "miniaturized, diversified" warheads.

"The North will carry out additional nuclear tests and continue to push for the development of miniaturized, diversified nuclear warheads," the NIS was quoted by lawmakers, who attended the audit, as saying.

“The third portal at the Punggye-ri site appears to be fully ready for a nuclear detonation, while the fourth portal may take considerable time to reach such a level of preparedness,” Korea Herald cited a press release from the National Assembly’s Intelligence Committee.

Yonhap said the agency also believes Kim Jong-un would seek to reprocess spent nuclear fuel rods at the Yongbyon nuclear complex later this year. The NIS added it had detected signs of Pyongyang attempting to hack into South Korea's financial institutions.

"We have detected circumstantial evidence that the North has persistently been trying to glean information needed for targeting and hacking into multiple financial institutions such as the virtual currency trading agency, banks and securities firms," the agency said.

"We anticipate that the North's hacking may focus on (extorting) virtual money that is hard to keep track of and may seek the destruction of the financial system, which could cause social confusion," it added.

The report by Yonhap about the possible nuclear test comes after CNN reported U.S. officials saying North Korea was working on an advanced version of the KN-20 intercontinental ballistic missile which could potentially reach the U.S. mainland.

The anonymous officials added the country might be working to fix a miniaturized warhead on top of the intercontinental missile. Other developments, according to the officials, may include improved solid rocket fuel with more stability, which burns hotter and more evenly to help the missile achieve greater distances; improved targeting and guidance systems and improved rocket motors and engine components.

Meanwhile, a high ranking North Korean defector, Thae Yong Ho, warned Wednesday that U.S. should tread with caution as striking first would trigger automatic retaliation by Kim Jong-un's regime.

“North Korean officers are trained to press their button without any further instructions from the general command if anything happens on their side,” Thae told the House Foreign Affairs Committee, according to the Associated Press. “We have to remember that tens of millions of South Korean population are living 70 to 80 kilometers away from the military demarcation line.”