North Korea threatened to deliver an “unimaginable strike” on the United States amid strained relations between Pyongyang and Washington over the rogue regime’s nuclear and missile programs.

“The U.S. is running amok by introducing under our nose the targets we have set as primary ones. The U.S. should expect that it would face unimaginable strike [sic] at an unimaginable time,” warned an unnamed North Koran agency in a statement reportedly published by the Pyongyang-controlled Korean Central News Agency (KCNA) on Thursday.

Reuters, citing the Russian-controlled RIA Novosti news agency the following day, reported that a North Korean diplomat indicated that dictator Kim Jong-un does not intend to conduct any discussions with the United States over its nuclear program, claiming that having nukes is a “matter of life and death for us.”

Choe Son-hui, the director-general of the North American department of North Korea’s foreign ministry, reportedly told a non-proliferation conference in Moscow that the United States would have to deal with North Korea’s nuclear capabilities.

“This is a matter of life and death for us. The current situation deepens our understanding that we need nuclear weapons to repel a potential attack,” he said. “We will respond to fire with fire.”

Pyongyang issued the threat as the South Korean and American navies are preparing massive joint exercises off the Korean Peninsula involving the U.S. aircraft carrier USS Ronald Reagan.

While urging the United States to embrace dialogue rather than pushing Pyongyang into “a corner,” President Vladimir Putin reportedly warned America that if it withdraws from its nuclear arms control treaty with the Kremlin, Russia would be forced to respond instantly and symmetrically.

“From our side, the response will be instant, and I want to warn, symmetrical,” cautioned Putin during the Valdai discussion forum with foreign academics in the Black Sea resort of Sochi.

During the event, he also cautioned that tensions between the United States and North Korea had reached a hazardous level.

Under dictator Kim Jong-un, North Korea has made numerous threats against the United States.

During a speech at the United Nations last month, U.S. President Donald Trump cautioned that America would “totally destroy” North Korea if necessary to defend itself and allies.

Trump and his predecessors have imposed numerous sanctions on the North Korean regime, but it continues to fire intercontinental ballistic missiles (ICBMs) and carry out nuclear tests.

In April, Gen. John Hyten, the chief of the U.S. Strategic Command (STRATCOM), cautioned that America is facing “significant challenges” sustaining its nuclear capabilities and is at risk of no longer holding a military advantage over enemies like North Korea and Russia.

Acting U.S. Department of Homeland Security Secretary Elaine Duke told lawmakers late last month that her department’s efforts to neutralize nuclear threats facing Americans are “inadequate.”