The commander of the U.S. Strategic Command, in charge of U.S. nuclear missile forces, confirmed on Thursday that North Korea is developing a submarine-launched ballistic missile (SLBM).

Adm. Cecil D. Haney, the commander, also told Congress that China is developing a new multi-warhead, road-mobile missile.

The four-star admiral made the comments in prepared testimony for the Senate Armed Services Committee. The testimony was disclosed Thursday.

The comments were the first official U.S. government confirmation that North Korea is working on a new underwater missile capability and comes as the regime in Pyongyang has tested nuclear weapons and claims to have miniaturized a weapon to fit on top of a missile.

The North Korean SLBM was first disclosed by the Free Beacon Aug. 26 amid skepticism that the communist state had the technical expertise to build a missile capable of being fired from a submerged submarine.

U.S. intelligence agencies detected the first flight test of what the Pentagon is calling the KN-11 SLBM in February. It was considered a significant advancement for North Korea’s program to build a nuclear-capable missile that can be fired from a submarine.

Haney testified on the Stratcom’s fiscal 2016 budget request and outlined what he called the "complex and dangerous global security environment."

"Nations around the world continue to execute long-term military modernization programs, including capabilities that pose an existential threat to the United States," Haney said, adding that military forces of nations and groups are "improving across all domains."

On North Korea, Haney said Pyongyang is continuing work to advance its nuclear weapons capabilities and claims to have "a miniaturized warhead capable of delivery by ballistic missile."

"At the same time, North Korea continues to advance its ballistic missile capability, including the development of a new road-mobile ballistic missile and a submarine-launched ballistic missile, and [to] develop its offensive cyber capabilities," he said.

The February test of the KN-11 followed a land-based ejection test in November from a static launcher at North Korea’s Sinpo South Shipyard, located on the southeastern coast about 100 miles from the Demilitarized Zone separating North Korea from rival South Korea.

Documents disclosed by Wikileaks revealed that North Korean obtained a SS-N-6 submarine-launched ballistic missile from Russia several years ago. That missile was adapted into Pyongyang’s Musudan intermediate-range ballistic missile.

North Korea also has deployed six KN-08 road-mobile intercontinental ballistic missiles that were developed with launchers supplied covertly by China.

As for submarines capable of launching missiles, North Korea obtained several decommissioned Soviet-era Golf II ballistic-missile submarines in the early 1990s. It is believed the North Koreans either refurbished the subs or copied their design for an indigenous submarine.

Russia also engaged in "troubling" activities last years, including long-range strategic bomber penetrations of U.S. and allied air defense zones, and strategic forces exercises during the Ukraine crisis.

"Russia has pursued more than a decade of investments and modernization across their strategic nuclear forces," Haney said. "Russia also has significant cyber capability, as evidenced by events in Estonia, Georgia and Ukraine."

Moscow also is building non-nuclear precision-strike, cyber warfare capabilities and space weapons, including anti-satellite arms.

Haney said China is using "low intensity coercion" in sovereignty disputes in the Asia Pacific and its space weapons developments also raise concerns about China’s global aspirations.

"China is using that wealth to modernize its strategic forces by enhancing existing silo-based ICBMs, conducting flight tests of a new mobile missile, and developing a follow-on mobile system capable of carrying multiple warheads," he said.

U.S. officials disclosed to the Free Beacon in October that China had conducted the first flight test of a new missile called the DF-31B. The new missile is believed to be a multi-warhead version of the DF-31A, a road-mobile missile that is difficult to track and can be launched with little warning, posing a greater strategic threat to the United States.

China also is testing new ballistic missile submarines and "developing multi-dimensional space capabilities supporting their access-denial campaign."

Access denial is Pentagon jargon for weapons that could be used to drive U.S. forces out of Asia and allow Beijing to become the dominant power there.

Haney also said China appears to be stepping up development of destructive space weapons, and has conducted cyber attacks on computer networks.

Haney also expressed worries about Iran’s nuclear activities, and said that there are increased concerns about Iranian cyber attacks.

On the terrorism front, Haney said that the natural biological threat of diseases such as Ebola are challenging but biological weapons in the hands of terrorists could be "catastrophic."

Haney also said that the Syrian regime of Bashir Assad continued to engage in the use of "toxic industrial chemicals" as weapons in the civil war.

On space threats, the commander said that space warfare developments in such states as Russia, China require greater efforts to secure space for peaceful uses.

Cyber threats to the United States are continuing to grow as both state-sponsored cyber attacks and non-state cyber groups target U.S. networks on a daily basis.

"Today, a small number of cyber actors have the potential to create large-scale damage," Haney said. "While most cyber threats can be characterized as criminal in nature, wide-ranging intrusions and attacks have threatened critical infrastructure and impacted commercial enterprise."

A new unconventional missile threat, according to Haney, is the mating of advanced weapons systems with commonplace items. He mentioned disguising surface-to-surface cruise missiles as shipping containers is one such threat. The technique is blurring the line between military and civilian systems and "complicates our deterrence calculus," he said.

Stratcom’s deterrence efforts involve more than just nuclear weapons, although nuclear forces remain the "ultimate guarantor of our security."

Other deterrent elements include intelligence systems, space systems, cyber capabilities, conventional weapons, and missile defenses.

"The likelihood of major conflict with other nuclear powers is remote today, and the ultimate U.S. goal remains the achievement of a world without nuclear weapons," he said. "Until that day comes, the U.S. requires a safe, secure and effective nuclear deterrent force, even as it continues to reduce its nuclear stockpile and the number of deployed nuclear warheads."

Haney called for continuing to invest in the modernization and upgrading of the America’s aging nuclear arsenal.

"Sustaining and modernizing the nuclear enterprise infrastructure—in physical and intellectual terms—is central to our long-term strategy," he said.