North Korean leader Kim Jong Un ordered his country to be ready to use its nuclear weapons at any time and the military to be in "pre-emptive attack" mode in the face of growing threats from its enemies, state media said on Friday. The comments, carried by the North's official KCNA news agency, marked a further escalation of tension on the Korean peninsula after the U.N. Security Council imposed harsh new sanctions against the isolated state on Wednesday for its nuclear program. North Korea, known for belligerent rhetoric, has previously threatened pre-emptive attacks on its enemies, including South Korea and the United States. Military experts doubt it has yet developed the capability to fire a long-range missile with a miniaturized warhead to deliver a nuclear weapon as far as the United States. Kim made the comments as he supervised military exercises involving newly developed rocket launchers, KCNA reported. It did not mention the date of the drills but said the new weapons had South Korea within range. South Korea's defense ministry said on Thursday North Korea launched several projectiles off its coast into the sea up to 150 kilometers (90 miles) away, an apparent response to the U.N. sanctions.

Kim said North Korea should "bolster up (its) nuclear force both in quality and quantity" and stressed "the need to get the nuclear warheads deployed for national defense always on standby so as to be fired any moment," KCNA quoted him as saying.

"Now is the time for us to convert our mode of military counteraction toward the enemies into a pre-emptive attack one in every aspect." Kim criticized South Korean President Park Geun-hye in his first direct published mention of her by name for acting "in league with the U.S. scoundrels," adding, "her hysteria will precipitate only her ruin in the long run," KCNA said.

A spokesman for South Korea's Unification Ministry, which handles relations with the North, said Kim's comments were not helpful and may have been intended for the domestic audience to boost morale in the face of the new U.N. sanctions.

A U.S. Defense Department spokesman, Commander Bill Urban, said, responding to the report: "We urge North Korea to refrain from provocative actions that aggravate tensions and instead focus on fulfilling its international obligations and commitments."

The latest U.N. sanctions, drafted by the United States and China, the North's main ally, punish the isolated country following its fourth nuclear test, in January, as well as last month's satellite launch, which the United States and others say was really a test of ballistic missile technology.

POSSIBLE ENGINE TEST EYED

South Korea and the U.S. militaries are set to formally begin talks on Friday on deployment of the advanced anti-missile Terminal High Altitude Area Defense (THAAD) system with the U.S. military in the South.

China and Russia oppose the deployment of THAAD, which has powerful radar capable of penetrating deep into their countries, but South Korea and the United States have said it was needed in response to the heightened missile threat from the North.