The United States said Sunday that North Korea's ballistic missile launches are unacceptable and vowed to show Pyongyang consequences in the event of such firings after North Korean leader Kim Jong-un strongly hinted the country is close to test-firing a long-range missile.

Kim said in his New Year's Day address that the communist nation has reached the final stage of preparations to test-fire an intercontinental ballistic missile in a veiled threat that it's about to develop a nuclear missile capable of reaching the US In response, the State Department said that any launches by the North using ballistic missile technology are explicitly banned under multiple UN Security Council resolutions.

"We call on all states to use every available channel and means of influence to make clear to the DPRK and its enablers that launches using ballistic missile technology are unacceptable, and take steps to show there are consequences to the DPRK's unlawful conduct," spokeswoman Anna Richey-Allen told Yonhap News Agency.

"We call on the DPRK to refrain from provocative actions and inflammatory rhetoric that threaten international peace and stability, and to make the strategic choice to fulfill its international obligations and commitments and return to serious talks," she said.

US experts have warned that the communist nation could undertake provocations around the time when incoming US President Donald Trump takes office on Jan. 20, noting Pyongyang has a record of staging provocations around US elections and transition periods.

Pyongyang is known to be developing a road-mobile ICBM, known as the KN-08, which is believed to have a range of more than 13,000 kilometers and could be capable of flying as far as the US mainland. But the North has never conducted an actual test of that missile.

Experts said that North Korea will focus on advancing its nuclear and missile capability in the new year, raising the possibility that it engages in more powerful provocations around its key anniversaries in the first half, including Kim's Jan. 8 birthday.

The KN-08 missile has been considered a key concern for the US, as the missile can be fired from mobile launchers and is harder to monitor. The US has steadily strengthened its missile defense system to guard against such threats.

In October, US Director of National Intelligence James Clapper said, referring to the KN-08, that the North is believed to be capable of launching "a missile that has a weapon on it that potentially could reach parts of the United States, certainly including Alaska and Hawaii."

The North has advanced ballistic missile technologies, and succeeded in putting satellites into orbit aboard long-range rockets twice, first in 2012 and again in February last year.

Experts say long-range rockets and ICBMs are basically the same with differences only in payloads.

Pyongyang has also conducted five nuclear tests, including two last year.

Experts have warned that it is only a matter of time until the North develops nuclear-tipped missiles. (Yonhap)