PYONGYANG, May 17 (Xinhua) -- The Democratic People's Republic of Korea (DPRK) has justified its latest long, medium-range ballistic missile test-firing as "routine work to raise nuclear capability for self-defense," rejecting a UN Security Council statement of condemnation.

"The successful test-fire of Hwasong-12 is of great and special significance in ensuring peace and stability in the Korean Peninsula and the region, and it is the greatest victory of the Korean people," a spokesman for the DPRK Foreign Ministry said Tuesday.

The DPRK is also stepping up diplomatic actions to seek support and understanding from other countries over its missile launch.

The DPRK Foreign Ministry on Monday briefed diplomatic envoys of the Association of Southeast Asian Nations (ASEAN) on the present situation, according to the official Korean Central News Agency (KCNA).

DPRK officials accused the United States of openly pressuring other countries into severing or degrading diplomatic ties with it by misusing "sanction resolutions" against it.

They were referring to a recent meeting between U.S. Secretary of State Rex Tillerson and ASEAN officials in Washington, during which Tillerson called on ASEAN countries to degrade diplomatic ties and cut commercial interactions with the DPRK.

"Such pressure by use of 'sanction resolutions' devoid of legality, morality and impartiality is a blatant infringement on the independence of a sovereign state and act of interference in others' internal affairs," said a senior DPRK diplomat at the briefing.

The DPRK test-fired a ballistic missile on Sunday which "accurately hit" the targeted open waters 787 km away after flying to a maximum altitude of 2,111.5 km, according to the KCNA.

Both the UN Security Council and Secretary-General Antonio Guterres on Monday slammed recent ballistic missile launches conducted by the DPRK.

The UN Security Council "strongly condemned the most recent ballistic missile launches" conducted by the DPRK on April 28 and May 13, the 15-nation UN body said in a press statement.