North Korea’s defence minister has warned the United States that the deployment of nuclear assets in South Korea could meet the conditions for its use of nuclear arms, according to state media.

Kang Sun Nam’s comments, reported on Thursday by the Korean Central News Agency (KCNA), came in response to the US sending a submarine with nuclear-armed ballistic missiles to South Korea this week for the first time in decades.

“The ever-increasing visibility of the deployment of the strategic nuclear submarine and other strategic assets may fall under the conditions of the use of nuclear weapons specified in the DPRK law,” Kang said in a statement, referring to his country by its official name, the Democratic People’s Republic of Korea.

Tensions between the US and North Korea have been on the rise in recent weeks with Pyongyang increasing its ballistic missile testing in defiance of Washington and international sanctions.

Late last week, the US, South Korea and Japan released a joint statement condemning the launch of a North Korean intercontinental ballistic missile days earlier.

“The United States reiterated that its commitments to defend the ROK [Republic of Korea, or South Korea] and Japan are ironclad and backed by the full range of capabilities, including nuclear,” the statement said.

The three allies went on to hold a joint military drill on Sunday.

On Wednesday, South Korea and Japan reported that North Korea had launched two more ballistic missiles.

The US and South Korea also held their first so-called Nuclear Consultative Group meeting this week. The White House said it provided a chance for the US to reaffirm its commitment to provide “extended deterrence” to South Korea.

“Any nuclear attack by North Korea against the United States or its allies is unacceptable and will result in the end of that regime, and the US and ROK sides highlighted that any nuclear attack by the DPRK against the ROK will be met with a swift, overwhelming, and decisive response,” the White House said in a statement after the talks.

On Thursday, North Korea slammed the nuclear meeting. “The phase of a military clash on the Korean Peninsula has surfaced as a dangerous reality,” the KCNA report said.